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  • 1.
    Afewerki, Samson
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Combined Catalysis: A Powerful Strategy for Engineering Multifunctional Sustainable Lignin-Based Materials2023In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 17, no 8, p. 7093-7108Article in journal (Refereed)
    Abstract [en]

    The production and engineering of sustainable materials through green chemistry will have a major role in our mission of transitioning to a more sustainable society. Here, combined catalysis, which is the integration of two or more catalytic cycles or activation modes, provides innovative chemical reactions and material properties efficiently, whereas the single catalytic cycle or activation mode alone fails in promoting a successful reaction. Polyphenolic lignin with its distinctive structural functions acts as an important template to create materials with versatile properties, such as being tough, antimicrobial, self-healing, adhesive, and environmentally adaptable. Sustainable lignin-based materials are generated by merging the catalytic cycle of the quinone-catechol redox reaction with free radical polymerization or oxidative decarboxylation reaction, which explores a wide range of metallic nanoparticles and metal ions as the catalysts. In this review, we present the recent work on engineering lignin-based multifunctional materials devised through combined catalysis. Despite the fruitful employment of this concept to material design and the fact that engineering has provided multifaceted materials able to solve a broad spectrum of challenges, we envision further exploration and expansion of this important concept in material science beyond the catalytic processes mentioned above. This could be accomplished by taking inspiration from organic synthesis where this concept has been successfully developed and implemented.

  • 2.
    Alizadehgiashi, Moien
    et al.
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada..
    Nemr, Carine R.
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada..
    Chekini, Mahshid
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada..
    Ramos, Daniel Pinto
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada..
    Mittal, Nitesh
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Fluid Physics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada.
    Ahmed, Sharif U.
    Univ Toronto, Dept Pharmaceut Sci, Toronto, ON M5S 3M2, Canada..
    Khuu, Nancy
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada..
    Kelley, Shana O.
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada.;Univ Toronto, Dept Pharmaceut Sci, Toronto, ON M5S 3M2, Canada.;Univ Toronto, Inst Biomat & Biomed Engn, Toronto, ON M5S 3G9, Canada..
    Kumacheva, Eugenia
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada.;Univ Toronto, Inst Biomat & Biomed Engn, Toronto, ON M5S 3G9, Canada.;Univ Toronto, Dept Chem Engn & Appl Chem, Toronto, ON M5S 3E5, Canada..
    Multifunctional 3D-Printed Wound Dressings2021In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 15, no 7, p. 12375-12387Article in journal (Refereed)
    Abstract [en]

    Personalized wound dressings provide enhanced healing for different wound types; however multicomponent wound dressings with discretely controllable delivery of different biologically active agents are yet to be developed. Here we report 3D-printed multicomponent biocomposite hydrogel wound dressings that have been selectively loaded with small molecules, metal nanoparticles, and proteins for independently controlled release at the wound site. Hydrogel wound dressings carrying antibacterial silver nanoparticles and vascular endothelial growth factor with predetermined release profiles were utilized to study the physiological response of the wound in a mouse model. Compared to controls, the application of dressings resulted in improvement in granulation tissue formation and differential levels of vascular density, dependent on the release profile of the growth factor. Our study demonstrates the versatility of the 3D-printed hydrogel dressings that can yield varied physiological responses in vivo and can further be adapted for personalized treatment of various wound types.

  • 3.
    Ansari, Farhan
    et al.
    Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA..
    Ding, Yichuan
    Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA..
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Dauskardt, Reinhold H.
    Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA..
    Toward Sustainable Multifunctional Coatings Containing Nanocellulose in a Hybrid Glass Matrix2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 6, p. 5495-5503Article in journal (Refereed)
    Abstract [en]

    We report on a sustainable route to protective nanocomposite coatings, where one of the components, nanocellulose fibrils, is derived from trees and the glass matrix is an inexpensive sol-gel organic-inorganic hybrid of zirconium alkoxide and an epoxy-functionalized silane. The hydrophilic nature of the colloidal nanocellulose fibrils is exploited to obtain a homogeneous one-pot suspension of the nanocellulose in the aqueous sol-gel matrix precursors solution. The mixture is then sprayed to form nano composite coatings of a well-dispersed, random in-plane nano cellulose fibril network in a continuous organic inorganic glass matrix phase. The nanocellulose incorporation in the sol-gel matrix resulted in nanostructured composites with marked effects on salient coating properties including optical transmittance, hardness, fracture energy, and water contact angle. The particular role of the nanocellulose fibrils on coating fracture properties, important for coating reliability, was analyzed and discussed in terms of fibril morphology, molecular matrix, and nanocellulose/matrix interactions.

  • 4. Carville, N. Craig
    et al.
    Manzo, Michele
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Damm, Signe
    Castiella, Marion
    Collins, Liam
    Denning, Denise
    Weber, Stefan
    Gallo, Katia
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Rice, James
    Rodriguez, Brian
    Photoreduction of SERS-Active Metallic Nanostructures on Chemically Patterned Ferroelectric Crystals2012In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 6, no 8, p. 7373-7380Article in journal (Refereed)
    Abstract [en]

    Photodeposition of metallic nanostructures onto ferroelectric surfaces is typically based on patterning local surface reactivity via electric field poling. Here, we demonstrate metal deposition onto substrates which have been chemically patterned via proton exchange (i.e., without polarization reversal). The chemical patterning provides the ability to tailor the electrostatic fields near the surface of lithium niobate crystals, and these engineered fields are used to fabricate metallic nanostructures. The effect of the proton exchange process on the piezoelectric and electrostatic properties of the surface is characterized using voltage-modulated atomic force microscopy techniques, which, combined with modeling of the electric fields at the surface of the crystal, reveal that the deposition occurs preferentially along the boundary between ferroelectric and proton-exchanged regions. The metallic nanostructures have been further functionalized with a target probe molecule, 4-aminothiophenol, from which surface-enhanced Raman scattering (SERS) signal is detected, demonstrating the suitability of chemically patterned ferroelectrics as SERS-active templates.

  • 5.
    Chen, Guanying
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ohulchanskyy, T. Y.
    Liu, S.
    Law, W. -C
    Wu, F.
    Swihart, M. T.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Prasad, P. N.
    Core/shell NaGdF 4:Nd 3+/NaGdF 4 nanocrystals with efficient near-infrared to near-infrared downconversion photoluminescence for bioimaging applications2012In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 6, no 4, p. 2969-2977Article in journal (Refereed)
    Abstract [en]

    We have synthesized core/shell NaGdF 4:Nd 3+/NaGdF 4 nanocrystals with an average size of 15 nm and exceptionally high photoluminescence (PL) quantum yield. When excited at 740 nm, the nanocrystals manifest spectrally distinguished, near-infrared to near-infrared (NIR-to-NIR) downconversion PL peaked at ∌900, ∌1050, and ∌1300 nm. The absolute quantum yield of NIR-to-NIR PL reached 40% for core-shell nanoparticles dispersed in hexane. Time-resolved PL measurements revealed that this high quantum yield was achieved through suppression of nonradiative recombination originating from surface states and cross relaxations between dopants. NaGdF 4:Nd 3+/NaGdF 4 nanocrystals, synthesized in organic media, were further converted to be water-dispersible by eliminating the capping ligand of oleic acid. NIR-to-NIR PL bioimaging was demonstrated both in vitro and in vivo through visualization of the NIR-to-NIR PL at ∌900 nm under incoherent lamp light excitation. The fact that both excitation and the PL of these nanocrystals are in the biological window of optical transparency, combined with their high quantum efficiency, spectral sharpness, and photostability, makes these nanocrystals extremely promising as optical biomaging probes.

  • 6.
    Chen, Guanying
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Shen, Jie
    Ohulchanskyy, Tymish Y.
    Patel, Nayan J.
    Kutikov, Artem
    Li, Zhipeng
    Song, Jie
    Pandey, Ravindra K.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Prasad, Paras N.
    Han, Gang
    (alpha-NaYbF4:Tm3+)/CaF2 Core/Shell Nanoparticles with Efficient Near-Infrared to Near-Infrared Upconversion for High-Contrast Deep Tissue Bioimaging2012In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 6, no 9, p. 8280-8287Article in journal (Refereed)
    Abstract [en]

    We describe the development of novel and biocompatible core/shell (alpha-NaYbF4:Tm3+)/CaF2 nanoparticles that exhibit highly efficient NIRin-NIROut upconversion (UC) for high contrast and deep bioimaging. When excited at similar to 980 nm, these nanoparticles emit photoluminescence (PL) peaked at similar to 800 nm. The quantum yield of this UC PL under low power density excitation (similar to 0.3 W/cm(2)) is 0.6 +/- 0.1%. This high UC PL efficiency is realized by suppressing surface quenching effects via heteroepitaxial growth of a biocompatible CaF2 shell, which results in a 35-fold increase in the intensity of UC PL from the core. Small-animal whole-body UC PL imaging with exceptional contrast (signal-to-background ratio of 310) is shown using BALB/c mice intravenously injected with aqueously dispersed nanoparticles (700 pmol/kg). High-contrast UC PL imaging of deep tissues is also demonstrated, using a nanoparticle-loaded synthetic fibrous mesh wrapped around rat femoral bone and a cuvette with nanoparticle aqueous dispersion covered with a 3.2 cm thick animal tissue (pork).

  • 7. Chen, H.
    et al.
    Xu, J.
    Wang, Y.
    Wang, D.
    Ferrer-Espada, R.
    Zhou, Jingjian
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Pedrazo-Tardajos, A.
    Yang, M.
    Tan, J. -H
    Yang, X.
    Zhang, L.
    Sychugov, Ilya
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Chen, S.
    Bals, S.
    Paulsson, J.
    Yang, Z.
    Color-Switchable Nanosilicon Fluorescent Probes2022In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 16, no 9, p. 15450-15459Article in journal (Refereed)
    Abstract [en]

    Fluorescent probes are vital to cell imaging by allowing specific parts of cells to be visualized and quantified. Color-switchable probes (CSPs), with tunable emission wavelength upon contact with specific targets, are particularly powerful because they not only eliminate the need to wash away all unbound probe but also allow for internal controls of probe concentrations, thereby facilitating quantification. Several such CSPs exist and have proven very useful, but not for all key cellular targets. Here we report a pioneering CSP for in situ cell imaging using aldehyde-functionalized silicon nanocrystals (SiNCs) that switch their intrinsic photoluminescence from red to blue quickly when interacting with amino acids in live cells. Though conventional probes often work better in cell-free extracts than in live cells, the SiNCs display the opposite behavior and function well and fast in universal cell lines at 37 °C while requiring much higher temperature in extracts. Furthermore, the SiNCs only disperse in cytoplasm not nucleus, and their fluorescence intensity correlated linearly with the concentration of fed amino acids. We believe these nanosilicon probes will be promising tools to visualize distribution of amino acids and potentially quantify amino acid related processes in live cells. 

  • 8. Chen, Si
    et al.
    Svedendahl, Mikael
    Antosiewicz, Tomasz J
    Käll, Mikael
    Plasmon-enhanced enzyme-linked immunosorbent assay on large arrays of individual particles made by electron beam lithography.2013In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 7, no 10Article in journal (Refereed)
    Abstract [en]

    Ultrasensitive biosensing is one of the main driving forces behind the dynamic research field of plasmonics. We have previously demonstrated that the sensitivity of single nanoparticle plasmon spectroscopy can be greatly enhanced by enzymatic amplification of the refractive index footprint of individual protein molecules, so-called plasmon-enhanced enzyme-linked immunosorbent assay (ELISA). The technique, which is based on generation of an optically dense precipitate catalyzed by horseradish peroxidase at the metal surface, allowed for colorimetric analysis of ultralow molecular surface coverages with a limit of detection approaching the single molecule limit. However, the plasmonic response induced by a single enzyme can be expected to vary for a number of reasons, including inhomogeneous broadening of the sensing properties of individual particles, variation in electric field enhancement over the surface of a single particle and variation in size and morphology of the enzymatic precipitate. In this report, we discuss how such inhomogeneities affect the possibility to quantify the number of molecules bound to a single nanoparticle. The discussion is based on simulations and measurements of large arrays of well-separated gold nanoparticles fabricated by electron beam lithography (EBL). The new data confirms the intrinsic single-molecule sensitivity of the technique but we were not able to clearly resolve the exact number of adsorbed molecules per single particle. The results indicate that the main sources of uncertainty come from variations in sensitivity across the surface of individual particles and between different particles. There is also a considerable uncertainty in the actual precipitate morphology produced by individual enzyme molecules. Possible routes toward further improvements of the methodology are discussed.

  • 9.
    Chen, Xi
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Chen, Yiting
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Nanosecond Photothermal Effects in Plasmonic Nanostructures2012In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 6, no 3, p. 2550-2557Article in journal (Refereed)
    Abstract [en]

    Photothermal effects in plasmonic nanostructures have great potentials in applications for photothermal cancer therapy, optical storage, thermo-photovoltaics, etc. However, the transient temperature behavior of a nanoscale material system during an ultrafast photothermal process has rarely been accurately investigated. Here a heat transfer model is constructed to investigate the temporal and spatial variation of temperature in plasmonic gold nanostructures. First, as a benchmark scenario, we study the light-induced heating of a gold nanosphere in water and calculate the relaxation time of the nanosphere excited by a modulated light. Second, we investigate heating and reshaping of gold nanoparticles in a more complex metamaterial absorber structure induced by a nanosecond pulsed light. The model shows that the temperature of the gold nanoparticles can be raised from room temperature to >795 K in just a few nanoseconds with a low light luminance, owing to enhanced light absorption through strong plasmonic resonance. Such quantitative predication of temperature change, which Is otherwise formidable to measure experimentally, can serve as an excellent guideline for designing devices for ultrafast photothermal applications.

  • 10. Ding, Fei
    et al.
    Wang, Zhuoxian
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering. Zhejiang University, China.
    Shalaev, Vladimir M.
    Kildishev, Alexander V.
    Broadband High-Efficiency Half-Wave Plate: A Supercell-Based Plasmonic Metasurface Approach2015In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 9, no 4, p. 4111-4119Article in journal (Refereed)
    Abstract [en]

    We design, fabricate, and experimentally demonstrate an ultrathin, broadband half-wave plate in the near-infrared range using a plasmonic metasurface. The simulated results show that the linear polarization conversion efficiency is over 97% with over 90% reflectance across an 800 nm bandwidth. Moreover, simulated and experimental results indicate that such broadband and high-efficiency performance is also sustained over a wide range of incident angles. To further obtain a background-free half-wave plate, we arrange such a plate as a periodic array of integrated supercells made of several plasmonic antennas with high linear polarization conversion efficiency, consequently achieving a reflection-phase gradient for the cross-polarized beam. In this design, the anomalous (cross-polarized) and the normal (copolarized) reflected beams become spatially separated, hence enabling highly efficient and robust, background-free polarization conversion along with broadband operation. Our results provide strategies for creating compact, integrated, and high-performance plasmonic circuits and devices.

  • 11.
    Enrico, Alessandro
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Hartwig, Oliver
    Institute of Physics, EIT 2, Faculty of Electrical Engineering and Information Technology, University of the Bundeswehr Munich & SENS Research Center, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany, Werner-Heisenberg-Weg 39.
    Dominik, Nikolas
    Institute of Physics, EIT 2, Faculty of Electrical Engineering and Information Technology, University of the Bundeswehr Munich & SENS Research Center, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany, Werner-Heisenberg-Weg 39.
    Quellmalz, Arne
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Gylfason, Kristinn
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Duesberg, Georg S.
    Institute of Physics, EIT 2, Faculty of Electrical Engineering and Information Technology, University of the Bundeswehr Munich & SENS Research Center, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany, Werner-Heisenberg-Weg 39.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Ultrafast and Resist-Free Nanopatterning of 2D Materials by Femtosecond Laser Irradiation2023In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 17, no 9, p. 8041-8052Article in journal (Refereed)
    Abstract [en]

    The performance of two-dimensional (2D) materials is promising for electronic, photonic, and sensing devices since they possess large surface-to-volume ratios, high mechanical strength, and broadband light sensitivity. While significant advances have been made in synthesizing and transferring 2D materials onto different substrates, there is still the need for scalable patterning of 2D materials with nanoscale precision. Conventional lithography methods require protective layers such as resist or metals that can contaminate or degrade the 2D materials and deteriorate the final device performance. Current resist-free patterning methods are limited in throughput and typically require custom-made equipment. To address these limitations, we demonstrate the noncontact and resist-free patterning of platinum diselenide (PtSe2), molybdenum disulfide (MoS2), and graphene layers with nanoscale precision at high processing speed while preserving the integrity of the surrounding material. We use a commercial, off-the-shelf two-photon 3D printer to directly write patterns in the 2D materials with features down to 100 nm at a maximum writing speed of 50 mm/s. We successfully remove a continuous film of 2D material from a 200 μm × 200 μm substrate area in less than 3 s. Since two-photon 3D printers are becoming increasingly available in research laboratories and industrial facilities, we expect this method to enable fast prototyping of devices based on 2D materials across various research areas.

  • 12.
    Eriksson, Mimmi
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Biosci & Mat Surface, Proc & Formulat, SE-11486 Stockholm, Sweden.
    Tuominen, Mikko
    RISE Res Inst Sweden, Biosci & Mat Surface, Proc & Formulat, SE-11486 Stockholm, Sweden..
    Jarn, Mikael
    RISE Res Inst Sweden, Biosci & Mat Surface, Proc & Formulat, SE-11486 Stockholm, Sweden..
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Research Institutes of Sweden, Bioscience and Materials − Surface, Process and Formulation, SE-114 86 Stockholm, Sweden.
    Wallqvist, Viveca
    RISE Res Inst Sweden, Biosci & Mat Surface, Proc & Formulat, SE-11486 Stockholm, Sweden..
    Butt, Hans Juergen
    Max Planck Inst Polymer Res, Dept Phys Interfaces, Ackermannweg 10, DE-55128 Mainz, Germany..
    Vollmer, Doris
    Max Planck Inst Polymer Res, Dept Phys Interfaces, Ackermannweg 10, DE-55128 Mainz, Germany..
    Kappl, Michael
    Max Planck Inst Polymer Res, Dept Phys Interfaces, Ackermannweg 10, DE-55128 Mainz, Germany..
    Schoelkopf, Joachim
    Omya Int AG, Baslerstr 42, CH-4665 Oftringen, Switzerland..
    Gane, Patrick A. C.
    Omya Int AG, Baslerstr 42, CH-4665 Oftringen, Switzerland.;Aalto Univ, Sch Chem Engn, Dept Bioprod & Biosyst, FI-00076 Aalto, Finland..
    Teisala, Hannu
    Max Planck Inst Polymer Res, Dept Phys Interfaces, Ackermannweg 10, DE-55128 Mainz, Germany..
    Swerin, Agne
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Biosci & Mat Surface, Proc & Formulat, SE-11486 Stockholm, Sweden..
    Direct Observation of Gas Meniscus Formation on a Superhydrophobic Surface2019In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 13, no 2, p. 2246-2252Article in journal (Refereed)
    Abstract [en]

    The formation of a bridging gas meniscus via cavitation or nanobubbles is considered the most likely origin of the submicrometer long-range attractive forces measured between hydrophobic surfaces in aqueous solution. However, the dynamics of the formation and evolution of the gas meniscus is still under debate, in particular, in the presence of a thin air layer on a superhydrophobic surface. On superhydrophobic surfaces the range can even exceed 10 mu m. Here, we report microscopic images of the formation and growth of a gas meniscus during force measurements between a superhydrophobic surface and a hydrophobic microsphere immersed in water. This is achieved by combining laser scanning confocal microscopy and colloidal probe atomic force microscopy. The configuration allows determination of the volume and shape of the meniscus, together with direct calculation of the Young-Laplace capillary pressure. The long-range attractive interactions acting on separation are due to meniscus formation and volume growth as air is transported from the surface layer.

  • 13. Fan, Ke
    et al.
    Zou, Haiyuan
    Lu, Yue
    Beijing Univ Technol, Inst Microstruct & Properties Adv Mat, Beijing 100124, Peoples R China..
    Chen, Hong
    Li, Fusheng
    Liu, Jinxuan
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Tong, Lianpeng
    Toney, Michael F.
    Sui, Manling
    Yu, Jiaguo
    Direct Observation of Structural Evolution of Metal Chalcogenide in Electrocatalytic Water Oxidation2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 12, p. 12369-12379Article in journal (Refereed)
    Abstract [en]

    As one of the most remarkable oxygen evolution reaction (OER) electrocatalysts, metal chalcogenides have been intensively reported during the past few decades because of their high OER activities. It has been reported that electron-chemical conversion of metal OER chalcogenides into oxides/hydroxides would take place after the OER. However, the transition mechanism of such unstable structures, as well as the real active sites and catalytic activity during the OER for these electrocatalysts, has not been understood yet; therefore a direct observation for the electrocatalytic water oxidation process, especially at nano or even angstrom scale, is urgently needed. In this research, by employing advanced Cs-corrected transmission electron microscopy (TEM), a step by step oxidational evolution of amorphous electrocatalyst CoSx into crystallized CoOOH in the OER has been in situ captured: irreversible conversion of CoSx to crystallized CoOOH is initiated on the surface of the electrocatalysts with a morphology change via Co(OH)(2) intermediate during the OER measurement, where CoOOH is confirmed as the real active species. Besides, this transition process has also been confirmed by multiple applications of X-ray photoelectron spectroscopy (XPS), in situ Fourier-transform infrared spectroscopy (FTIR), and other ex situ technologies. Moreover, on the basis of this discovery, a high-efficiency electrocatalyst of a nitrogen-doped graphene foam (NGF) coated by CoSx has been explored through a thorough structure transformation of CoOOH. We believe this in situ and in-depth observation of structural evolution in the OER measurement can provide insights into the fundamental understanding of the mechanism for the OER catalysts, thus enabling the more rational design of low-cost and high-efficient electrocatalysts for water splitting.

  • 14.
    Fang, Trixy
    et al.
    Karolinska Inst, Dept Med Biochem & Biophys, S-17165 Stockholm, Sweden..
    Alvelid, Jonatan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biophysics. KTH Royal Inst Technol, Dept Appl Phys & Sci Life Lab, S-10044 Stockholm, Sweden..
    Spratt, Joel
    Karolinska Inst, Dept Med Biochem & Biophys, S-17165 Stockholm, Sweden..
    Ambrosetti, Elena
    Karolinska Inst, Dept Med Biochem & Biophys, S-17165 Stockholm, Sweden..
    Testa, Ilaria
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH Royal Inst Technol, Dept Appl Phys & Sci Life Lab, S-10044 Stockholm, Sweden..
    Teixeira, Ana, I
    Karolinska Inst, Dept Med Biochem & Biophys, S-17165 Stockholm, Sweden..
    Spatial Regulation of T-Cell Signaling by Programmed Death-Ligand 1 on Wireframe DNA Origami Flat Sheets2021In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 15, no 2, p. 3441-3452Article in journal (Refereed)
    Abstract [en]

    Programmed Death-1 (PD-1) is a coinhibitory receptor expressed on activated T cells that suppresses T-cell signaling and effector functions. It has been previously shown that binding to its ligand PD-L1 induces a spatial reorganization of PD-1 receptors into microclusters on the cell membrane. However, the roles of the spatial organization of PD-L1 on PD-1 clustering and T-cell signaling have not been elucidated. Here, we used DNA origami flat sheets to display PD-L1 ligands at defined nanoscale distances and investigated their ability to inhibit T-cell activation in vitro. We found that DNA origami flat sheets modified with CD3 and CD28 activating antibodies (FS-alpha-CD3-CD28) induced robust T-cell activation. Co-treatment with flat sheets presenting PD-L1 ligands separated by similar to 200 nm (FS-PD-L1-200), but not 13 nm (FS-PD-L1-13) or 40 nm (FS-PD-L1-40), caused an inhibition of T-cell signaling, which increased with increasing molar ratio of FS-PD-L1-200 to FS-alpha-CD3-CD28. Furthermore, FS-PD-L1-200 induced the formation of smaller PD-1 nanoclusters and caused a larger reduction in IL-2 expression compared to FS-PD-L1-13. Together, these findings suggest that the spatial organization of PD-L1 determines its ability to regulate T-cell signaling and may guide the development of future nanomedicine-based immunomodulatory therapies.

  • 15.
    Finizio, Simone
    et al.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland..
    Bailey, Joe Bilko
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.;Ecole Polytech Fed Lausanne, Inst Phys, CH-1015 Lausanne, Switzerland..
    Olsthoorn, Bart
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA. KTH, School of Engineering Sciences (SCI), Physics, Condensed Matter Theory. Stockholm Univ, SE-10691 Stockholm, Sweden..
    Raabe, Joerg
    Periodogram-Based Detection of Unknown Frequencies in Time-Resolved Scanning Transmission X-ray Microscopy2022In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 16, no 12, p. 21071-21078Article in journal (Refereed)
    Abstract [en]

    Pump-probe time-resolved imaging is a powerful technique that enables the investigation of dynamical processes. Signal-to-noise and sampling rate restrictions normally require that cycles of an excitation are repeated many times with the final signal reconstructed using a reference. However, this approach imposes restrictions on the types of dynamical processes that can be measured, namely, that they are phase locked to a known external signal (e.g., a driven oscillation or impulse). This rules out many interesting processes such as auto-oscillations and spontaneously forming populations, e.g., condensates. In this work we present a method for time-resolved imaging, based on the Schuster periodogram, that allows for the reconstruction of dynamical processes where the intrinsic frequency is not known. In our case we use time of arrival detection of X-ray photons to reconstruct magnetic dynamics without using a priori information on the dynamical frequency. This proof-of-principle demonstration will allow for the extension of pump-probe time-resolved imaging to the important class of processes where the dynamics are not locked to a known external signal and in its presented formulation can be readily adopted for X-ray imaging and also adapted for wider use.

  • 16.
    Garemark, Jonas
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Perea-Buceta, Jesus E.
    Materials Chemistry Division, Department of Chemistry, Faculty of Science, University of Helsinki, 00560 Helsinki, Finland.
    Felhofer, Martin
    Department of Nanobiotechnology, Institute of Biophysics, University of Natural Resources and Life Sciences, Vienna, Austria.
    Chen, Bin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Cortes Ruiz, Maria F.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Sapouna, Ioanna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Gierlinger, Notburga
    Department of Nanobiotechnology, Institute of Biophysics, University of Natural Resources and Life Sciences, Vienna, Austria.
    Kilpeläinen, Ilkka
    Materials Chemistry Division, Department of Chemistry, Faculty of Science, University of Helsinki, 00560Helsinki, Finland..
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Li, Yuanyuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Strong, Shape-Memory Aerogel via Wood Cell Wall Nanoscale Reassembly2023In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 17, no 5, p. 4775-4789Article in journal (Refereed)
    Abstract [en]

    Polymer shape-memory aerogels (PSMAs) are prospects in various fields of application ranging from aerospace to biomedicine, as advanced thermal insulators, actuators, or sensors. However, the fabrication of PSMAs with good mechanical performance is challenging and is currently dominated by fossil-based polymers. In this work, strong, shape-memory bio-aerogels with high specific surface areas (up to 220 m2/g) and low radial thermal conductivity (0.042 W/mK) were prepared through a one-step treatment of native wood using an ionic liquid mixture of [MTBD]+[MMP]−/DMSO. The aerogel showed similar chemical composition similar to native wood. Nanoscale spatial rearrangement of wood biopolymers in the cell wall and lumen was achieved, resulting in flexible hydrogels, offering design freedom for subsequent aerogels with intricate geometries. Shape-memory function under stimuli of water was reported. The chemical composition and distribution, morphology, and mechanical performance of the aerogel were carefully studied using confocal Raman spectroscopy, AFM, SAXS/WAXS, NMR, digital image correlation, etc. With its simplicity, sustainability, and the broad range of applicability, the methodology developed for nanoscale reassembly of wood is an advancement for the design of biobased shape-memory aerogels.

  • 17.
    Garemark, Jonas
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Yang, Xuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Sheng, Xia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Ocean, Cheung
    Department of Engineering Sciences, Nanotechnology and Functional Materials, Uppsala University, 75121 Uppsala, Sweden.
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Li, Yuanyuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Top-Down Approach Making Anisotropic Cellulose Aerogels as Universal Substrates for Multifunctionalization2020In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 14, no 6, p. 7111-7120Article in journal (Refereed)
    Abstract [en]

    Highly porous, strong aerogels with anisotropicstructural properties are of great interest for multifunctionalmaterials for applications including insulators in buildings,filters for oil cleanup, electrical storage devices,etc. Contem-porary aerogels are mostly extracted from fossil resources andsynthesized from bottom-up techniques, often requiring addi-tional strategies to obtain high anisotropy. In this work, auniversal approach to prepare porous, strong, anisotropicaerogels is presented through exploiting the natural hierarchicaland anisotropic structure of wood. The preparation comprisesnanoscale removal of lignin, followed by dissolution−regener-ation of nanofibers, leading to enhanced cell wall porosity with nanofibrillated networks occupying the pore space in thecellular wood structure. The aerogels retain structural anisotropy of natural wood, exhibit specific surface areas up to 247 m2/g, and show high compression strength at 95% porosity. This is a record specific area value for wood aerogels/foams and evenhigher than most cellulose-based aerogels for its assigned strength. The aerogel can serve as a platform for multifunctionalcomposites including scaffolds for catalysis, gas separation, or liquid purification due to its porous matrix or as binder-freeelectrodes in electronics. To demonstrate the multifunctionality, the aerogels are successfully decorated with metalnanoparticles (Ag) and metal oxide nanoparticles (TiO2)byin situsynthesis, coated by the conductive polymer(PEDOT:PSS), and carbonized to yield conductive aerogels. This approach is found to be a universal way to prepare highlyporous anisotropic aerogels.

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  • 18.
    Gowda, V. Krishne
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Rosén, Tomas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. DESY, D-22607 Hamburg, Germany..
    Söderberg, Daniel
    KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fiberprocesser.
    Lundell, Fredrik
    KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Nanofibril Alignment during Assembly Revealed by an X-ray Scattering-Based Digital Twin2022In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 16, no 2, p. 2120-2132Article in journal (Refereed)
    Abstract [en]

    The nanostructure, primarily particle orientation, controls mechanical and functional (e.g., mouthfeel, cell compatibility, optical, morphing) properties when macroscopic materials are assembled from nanofibrils. Understanding and controlling the nanostructure is therefore an important key for the continued development of nanotechnology. We merge recent developments in the assembly of biological nanofibrils, X-ray diffraction orientation measurements, and computational fluid dynamics of complex flows. The result is a digital twin, which reveals the complete particle orientation in complex and transient flow situations, in particular the local alignment and spatial variation of the orientation distributions of different length fractions, both along the process and over a specific cross section. The methodology forms a necessary foundation for analysis and optimization of assembly involving anisotropic particles. Furthermore, it provides a bridge between advanced in operandi measurements of nanostructures and phenomena such as transitions between liquid crystal states and in silico studies of particle interactions and agglomeration.

  • 19.
    Guan, Tianfu
    et al.
    Tech Univ Munich, TUM Sch Nat Sci, Dept Phys, Chair Funct Mat, D-85748 Garching, Germany..
    Chen, Wei
    Tech Univ Munich, TUM Sch Nat Sci, Dept Phys, Chair Funct Mat, D-85748 Garching, Germany.;Shenzhen Technol Univ, Ctr Adv Mat Diagnost Technol, Shenzhen Key Lab Ultraintense Laser & Adv Mat Tech, Shenzhen 518118, Peoples R China.;Shenzhen Technol Univ, Coll Engn Phys, Shenzhen 518118, Peoples R China..
    Tang, Haodong
    Shenzhen Technol Univ, Coll Integrated Circuits & Optoelect Chips, Shenzhen 518118, Peoples R China..
    Li, Dong
    Soochow Univ, Inst Funct Nano & Soft Mat FUNSOM, Jiangsu Key Lab Carbon Based Funct Mat & Devices, Suzhou 215123, Peoples R China..
    Wang, Xiao
    Shenzhen Technol Univ, Ctr Adv Mat Diagnost Technol, Shenzhen Key Lab Ultraintense Laser & Adv Mat Tech, Shenzhen 518118, Peoples R China.;Shenzhen Technol Univ, Coll Engn Phys, Shenzhen 518118, Peoples R China..
    Weindl, Christian L.
    Tech Univ Munich, TUM Sch Nat Sci, Dept Phys, Chair Funct Mat, D-85748 Garching, Germany..
    Wang, Yawen
    Soochow Univ, Inst Funct Nano & Soft Mat FUNSOM, Jiangsu Key Lab Carbon Based Funct Mat & Devices, Suzhou 215123, Peoples R China..
    Liang, Zhiqiang
    Soochow Univ, Inst Funct Nano & Soft Mat FUNSOM, Jiangsu Key Lab Carbon Based Funct Mat & Devices, Suzhou 215123, Peoples R China..
    Liang, Suzhe
    Tech Univ Munich, TUM Sch Nat Sci, Dept Phys, Chair Funct Mat, D-85748 Garching, Germany..
    Xiao, Tianxiao
    Tech Univ Munich, TUM Sch Nat Sci, Dept Phys, Chair Funct Mat, D-85748 Garching, Germany..
    Tu, Suo
    Tech Univ Munich, TUM Sch Nat Sci, Dept Phys, Chair Funct Mat, D-85748 Garching, Germany..
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fiberprocesser. Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Jiang, Lin
    Soochow Univ, Inst Funct Nano & Soft Mat FUNSOM, Jiangsu Key Lab Carbon Based Funct Mat & Devices, Suzhou 215123, Peoples R China..
    Mueller-Buschbaum, Peter
    Tech Univ Munich, TUM Sch Nat Sci, Dept Phys, Chair Funct Mat, D-85748 Garching, Germany.;Tech Univ Munich, Heinz Maier Leibnitz Zent MLZ, D-85748 Garching, Germany..
    Decoding the Self-Assembly Plasmonic Interface Structure in a PbS Colloidal Quantum Dot Solid for a Photodetector2023In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 17, no 22, p. 23010-23019Article in journal (Refereed)
    Abstract [en]

    Hybrid plasmonic nanostructures have gained enormous attention in a variety of optoelectronic devices due to their surface plasmon resonance properties. Self-assembled hybrid metal/quantum dot (QD) architectures offer a means of coupling the properties of plasmonics and QDs to photodetectors, thereby modifying their functionality. The arrangement and localization of hybrid nanostructures have an impact on exciton trapping and light harvesting. Here, we present a hybrid structure consisting of self-assembled gold nanospheres (Au NSs) embedded in a solid matrix of PbS QDs for mapping the interface structures and the motion of charge carriers. Grazing-incidence small-angle X-ray scattering is utilized to analyze the localization and spacing of the Au NSs within the hybrid structure. Furthermore, by correlating the morphology of the Au NSs in the hybrid structure with the corresponding differences observed in the performance of photodetectors, we are able to determine the impact of interface charge carrier dynamics in the coupling structure. From the perspective of architecture, our study provides insights into the performance improvement of optoelectronic devices.

  • 20.
    Hamedi, Mahiar M.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hajian, Alireza
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Fall, Andreas B.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Håkansson, Karl
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Salajkova, Michaela
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lundell, Fredrik
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Highly Conducting, Strong Nanocomposites Based on Nanocellulose-Assisted Aqueous Dispersions of Single-Wall Carbon Nanotubes2014In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 8, no 3, p. 2467-2476Article in journal (Refereed)
    Abstract [en]

    It is challenging to obtain high-quality dispersions of single-wall nanotubes (SWNTs) in composite matrix materials, in order to reach the full potential of mechanical and electronic properties. The most widely used matrix materials are polymers, and the route to achieving high quality dispersions of SWNT is mainly chemical functionalization of the SWNT. This leads to increased cost, a loss of strength and lower conductivity. In addition full potential of colloidal self-assembly cannot be fully exploited in a polymer matrix. This may limit the possibilities for assembly of highly ordered structural nanocomposites. Here we show that nanofibrillated cellulose (NFC) can act as an excellent aqueous dispersion agent for as-prepared SWNTs, making possible low-cost exfoliation and purification of SWNTs with dispersion limits exceeding 40 wt %. The NFC:SWNT dispersion may also offer a cheap and sustainable alternative for molecular self-assembly of advanced composites. We demonstrate semitransparent conductive films, aerogels and anisotropic microscale fibers with nanoscale composite structure. The NFC:SWNT nanopaper shows increased strength at 3 wt % SWNT, reaching a modulus of 133 GPa, and a strength of 307 MPa. The anisotropic microfiber composites have maximum conductivities above 200 S cm(-1) and current densities reaching 1400 A cm(-2).

  • 21.
    Huang, Bingru
    et al.
    South China Normal Univ, South China Acad Adv Optoelect, Ctr Opt & Electromagnet Res, Guangdong Prov Key Lab Opt Informat Mat & Technol, Guangzhou 510006, Guangdong, Peoples R China.
    Bergstrand, Jan
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Duan, Sai
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Zhan, Qiuqiang
    South China Normal Univ, South China Acad Adv Optoelect, Ctr Opt & Electromagnet Res, Guangdong Prov Key Lab Opt Informat Mat & Technol, Guangzhou 510006, Guangdong, Peoples R China.
    Widengren, Jerker
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Ågren, Hans
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Liu, Haichun
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Overtone Vibrational Transition-Induced Lanthanide Excited-State Quenching in Yb3+/Er3+-Doped Upconversion Nanocrystals2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, p. 10572-10575Article in journal (Refereed)
  • 22.
    Hyun, Gyu Hwan
    et al.
    College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea.
    Jeong, Da-Hye
    Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea;Department of Biomedical Sciences, Graduate School of Ajou University, Suwon 16499, Republic of Korea.
    Yang, Yoon Young
    College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea.
    Cho, In Ho
    College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea.
    Ha, Yu-Jin
    Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea;Department of Biomedical Sciences, Graduate School of Ajou University, Suwon 16499, Republic of Korea.
    Xing, Xiaohui
    Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta T1J 4B1, Canada.
    Abbott, D. Wade
    Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta T1J 4B1, Canada.
    Hsieh, Yves S. Y.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience. School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 11031, Taiwan.
    Kang, Yun Pyo
    College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea.
    Cha, Jong-Ho
    Department of Biomedical Science, College of Medicine, and Program in Biomedical Sciences and Engineering, Inha University, Incheon 22332, Republic of Korea.
    Hong, Soon-Sun
    Department of Biomedical Science, College of Medicine, and Program in Biomedical Sciences and Engineering, Inha University, Incheon 22332, Republic of Korea.
    Lee, Seul Ji
    College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea;College of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea.
    Kim, You-Sun
    Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea;Department of Biomedical Sciences, Graduate School of Ajou University, Suwon 16499, Republic of Korea.
    Kwon, Sung Won
    College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea.
    Multivalent Carbohydrate Nanocomposites for Tumor Microenvironment Remodeling to Enhance Antitumor Immunity2023In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 17, no 12, p. 11567-11582Article in journal (Refereed)
    Abstract [en]

    Current cancer immunotherapeutic strategies mainly focus on remodeling the tumor microenvironment (TME) to make it favorable for antitumor immunity. Increasing attention has been paid to developing innovative immunomodulatory adjuvants that can restore weakened antitumor immunity by conferring immunogenicity to inflamed tumor tissues. Here, a galactan-enriched nanocomposite (Gal-NC) is developed from native carbohydrate structures through an optimized enzymatic transformation for effective, stable, and biosafe innate immunomodulation. Gal-NC is characterized as a carbohydrate nanoadjuvant with a macrophage-targeting feature. It is composed of repeating galactan glycopatterns derived from heteropolysaccharide structures of plant origin. The galactan repeats of Gal-NC function as multivalent pattern-recognition sites for Toll-like receptor 4 (TLR4). Functionally, Gal-NC-mediated TLR activation induces the repolarization of tumor-associated macrophages (TAMs) toward immunostimulatory/tumoricidal M1-like phenotypes. Gal-NC increases the intratumoral population of cytotoxic T cells, the main effector cells of antitumor immunity, via re-educated TAMs. These TME alterations synergistically enhance the T-cell-mediated antitumor response induced by αPD-1 administration, suggesting that Gal-NC has potential value as an adjuvant for immune checkpoint blockade combination therapies. Thus, the Gal-NC model established herein suggests a glycoengineering strategy to design a carbohydrate-based nanocomposite for advanced cancer immunotherapies.

  • 23. Jana, Avijit
    et al.
    Nguyen, Kim Truc
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhu, Pengcheng
    Tan, Nguan Soon
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhao, Yanli
    Perylene-Derived Single-Component Organic Nanoparticles with Tunable Emission: Efficient Anticancer Drug Carriers with Real-Time Monitoring of Drug Release2014In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 8, no 6, p. 5939-5952Article in journal (Refereed)
    Abstract [en]

    An organic nanoparticle-based drug delivery system with high drug loading efficacy (similar to 79 wt %) was developed using a perylene-derived photoremovable protecting group, namely, perylene-3,4,9,10-tetrayltetramethanol (Pe(OH)(4)). The anticancer drug chlorambucil was protected by coupling with Pe(OH)(4) to form photocaged nanoparticles (Pe(OH)(4)). The photorelease mechanism of chlorambucil from the Pe(Cbl)(4) conjugate was investigated experimentally by high-resolution mass spectrometry and theoretically by density functional theory calculations. The Pe(Cbl)(4) nanoparticles perform four important roles: (i) a nanocarrier for drug delivery, (ii) a phototrigger for drug release, (iii) a fluorescent chromophore for cell imaging, and (iv) a photoswitchable fluorophore for real-time monitoring of drug release. Tunable emission of the perylene-derived nanoparticles was demonstrated by comparing the emission properties of the Pe(OH)(4) and Pe(Cbl)(4) nanoparticles with perylene-3-ylmethanol. These nanoparticles were subsequently employed in cell imaging for investigating their intracellular localization. Furthermore, the in vivo toxicity of the Pe(OH)(4) nanoparticles was investigated using the mouse model. Histological tissue analysis of five major organs, i.e., heart, kidney, spleen, liver, and lung, indicates that the nanoparticles did not show any obvious damage to these major organs under the experimental conditions. The current research presents a successful example of integrating multiple functions into single-component organic nanoparticles for drug delivery.

  • 24.
    Ji, Shaozheng
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Granas, Oscar
    Uppsala Univ, Dept Phys & Astron, Div Mat Theory, SE-75120 Uppsala, Sweden..
    Weissenrieder, Jonas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Manipulation of Stacking Order in Td-WTe2 by Ultrafast Optical Excitation2021In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 15, no 5, p. 8826-8835Article in journal (Refereed)
    Abstract [en]

    Subtle changes in stacking order of layered transition metal dichalcogenides may have profound influence on the electronic and optical properties. The intriguing electronic properties of Td-WTe2 can be traced to the break of inversion symmetry resulting from the ground-state stacking sequence. Strategies for perturbation of the stacking order are actively pursued for intentional tuning of material properties, where optical excitation is of specific interest since it holds the potential for integration of ultrafast switches in future device designs. Here we investigate the structural response in Td-WTe2 following ultrafast photoexcitation by time-resolved electron diffraction. A 0.23 THz shear phonon, involving layer displacement along the b axis, was excited by a 515 nm laser pulse. Pump fluences in excess of a threshold of similar to 1 mJ/cm(2) result in formation, with an similar to 5 ps time constant, of a new stacking order by layer displacement along the b axis in the direction toward the centrosymmetric 1T* phase. The shear displacement of the layers increases with pump fluence until saturation at similar to 8 pm. We demonstrate that the excitation of the shear phonon and the stabilization of the metastable phase are decoupled when using an optical pump as evidenced by observation of a transition also in samples with a pinned shear phonon. The results are compared to dynamic first-principles simulations and the transition is interpreted in terms of a mechanism where transient local disorder is prominent before settling at the atomic positions of the metastable phase. This interpretation is corroborated by results from diffuse scattering. The correlation between excitation of intralayer vibrations and interlayer interaction demonstrates the importance of including both short- and long-range interactions in an accurate description of how optical fields can be employed to manipulate the stacking order in 2-dimensional transition metal dichalcogenides.

  • 25.
    Karabulut, Erdem
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Ankerfors, Mikael
    Material Processes, Innventia AB, Stockholm, Sweden.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Adhesive Layer-by-Layer Films of Carboxymethylated Cellulose Nanofibril Dopamine Covalent Bioconjugates Inspired by Marine Mussel Threads2012In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 6, no 6, p. 4731-4739Article in journal (Refereed)
    Abstract [en]

    The preparation of multifunctional films and coatings from sustainable, low-cost raw materials has attracted considerable interest during the past decade. In this respect, cellulose-based products possess great promise due not only to the availability of large amounts of cellulose in nature but also to the new classes of nanosized and well-characterized building blocks of cellulose being prepared from trees or annual plants. However, to fully utilize the inherent properties of these nanomaterials, facile and also sustainable preparation routes are needed. In this work, bioinspired hybrid conjugates of carboxymethylated cellulose nanofibrils (CNFC) and dopamine (DOPA) have been prepared and layer-by-layer (LbL) films of these modified nanofibrils have been built up in combination with a branched polyelectrolyte, polyethyleneimine (PEI), to obtain robust, adhesive, and wet-stable nanocoatings on solid surfaces. It is shown that the chemical functionalization of CNFCs with DOPA molecules alters their conventional properties both in liquid dispersion and at the interface and also influences the LbL. film formation by reducing the electrostatic interaction. Although the CNFC-DOPA conjugates show a lower colloidal stability in aqueous dispersions due to charge suppression, it was possible to prepare the LbL films through the consecutive deposition of the building blocks. Adhesive forces between muttilayer films prepared using chemically functionalized CNFCs and a silica probe are much stronger in the presence of Fe3+ than those between a multilayer film prepared from unmodified nanofibrils and a silica probe. The present work demonstrates a facile way to prepare chemically functionalized cellulose nanofibrils whereby more extended applications can produce novel cellulose-based materials with different functionalities.

  • 26.
    Kilwing, Luzia
    et al.
    Ludwig Maximilians Univ Munchen, Fac Phys, D-80539 Munich, Germany.;Ludwig Maximilians Univ Munchen, Ctr Nanosci CeNS, D-80539 Munich, Germany.;Harvard Med Sch, Dana Farber Canc Inst, Dept Canc Biol, Boston, MA 02115 USA.;Harvard Med Sch, Dept Biol Chem & Mol Pharmacol, Boston, MA 02115 USA..
    Lill, Pascal
    Harvard Med Sch, Dana Farber Canc Inst, Dept Canc Biol, Boston, MA 02115 USA.;Harvard Med Sch, Dept Biol Chem & Mol Pharmacol, Boston, MA 02115 USA..
    Nathwani, Bhavik
    Harvard Med Sch, Dana Farber Canc Inst, Dept Canc Biol, Boston, MA 02115 USA.;Harvard Med Sch, Dept Biol Chem & Mol Pharmacol, Boston, MA 02115 USA..
    Guerra, Richard
    Harvard Med Sch, Dana Farber Canc Inst, Dept Canc Biol, Boston, MA 02115 USA.;Harvard Med Sch, Dept Biol Chem & Mol Pharmacol, Boston, MA 02115 USA..
    Benson, Erik
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Gene Technology. Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England.;Univ Oxford, Kavli Inst Nanosci Discovery, Oxford OX1 3PU, England.
    Liedl, Tim
    Ludwig Maximilians Univ Munchen, Fac Phys, D-80539 Munich, Germany.;Ludwig Maximilians Univ Munchen, Ctr Nanosci CeNS, D-80539 Munich, Germany..
    Shih, William M.
    Harvard Med Sch, Dana Farber Canc Inst, Dept Canc Biol, Boston, MA 02115 USA.;Harvard Med Sch, Dept Biol Chem & Mol Pharmacol, Boston, MA 02115 USA..
    Multilayer DNA Origami with Terminal Interfaces That Are Flat and Wide-Area2023In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 18, no 1, p. 885-893Article in journal (Refereed)
    Abstract [en]

    DNA origami is a popular nanofabrication strategy that employs self-assembly of a long single scaffold strand, typically less than 10 kilobases in length, with hundreds of shorter staple strands into a desired shape. In particular, origami arranged as a single-layer rectangle has proven popular as flat pegboards that can display functionalities at staple-strand breakpoints, off the sides of the constituent double helices, with a similar to 5.3 nm rhombic-lattice spacing. For applications that demand tighter spacing, functionalities can be displayed instead on the termini of helices of multilayer DNA origami. However, pegboards with the greatest addressable surface area are often found to be the most versatile. Given the practical limitations of the length of the scaffold that can be easily realized, designs that minimize the length of each helix would have advantages for maximizing the number of helices and therefore the number of addressable pixels on each terminal surface. Here we present an architecture for multilayer DNA origami displaying flush terminal interfaces from over 200 helices that each are only 5.3 turns in length. We characterize an example using cryo-EM imaging paired with single-particle analysis for further analysis of the global structure.

  • 27. Kimna, Ceren
    et al.
    Lutz, Theresa Monika
    Yan, Hongji
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience.
    Song, Jian
    Crouzier, Thomas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience.
    Lieleg, Oliver
    DNA Strands Trigger the Intracellular Release of Drugs from Mucin-Based Nanocarriers2021In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 15, no 2, p. 2350-2362Article in journal (Refereed)
    Abstract [en]

    Gaining control over the delivery of therapeutics to a specific disease site is still very challenging. However, especially when cytotoxic drugs such as chemotherapeutics are used, the importance of a control mechanism that can differentiate "sick" target cells from the surrounding healthy tissue is pivotal. Here, we designed a nanoparticle-based drug delivery process, which releases an active agent only in the presence of a specific trigger DNA sequence. With this strategy, we are able to initiate the release of therapeutics into the cytosol with high efficiency. Furthermore, we demonstrate how an endogenous marker (e.g., a specific miRNA sequence) that is overexpressed in the initial phases of certain cancer types can be used as a stimulus to autonomously initiate intracellular drug release-and only in cells where this pathophysiological marker is present. We expect that this precisely controlled delivery mechanism can facilitate the design of site-specific treatments for such diseases, where an overexpression of signature oligonucleotide sequences has been identified.

  • 28.
    Lai, Lee-Lun
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Huang, Po-Han
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Gylfason, Kristinn B.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    3D Printing of Glass Micro-Optics with Subwavelength Features on Optical Fiber Tips2024In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 18, no 16, p. 10788-10797Article in journal (Refereed)
    Abstract [en]

    Integration of functional materials and structures on the tips of optical fibers has enabled various applications in micro-optics, such as sensing, imaging, and optical trapping. Direct laser writing is a 3D printing technology that holds promise for fabricating advanced micro-optical structures on fiber tips. To date, material selection has been limited to organic polymer-based photoresists because existing methods for 3D direct laser writing of inorganic materials involve high-temperature processing that is not compatible with optical fibers. However, organic polymers do not feature stability and transparency comparable to those of inorganic glasses. Herein, we demonstrate 3D direct laser writing of inorganic glass with a subwavelength resolution on optical fiber tips. We show two distinct printing modes that enable the printing of solid silica glass structures (“Uniform Mode”) and self-organized subwavelength gratings (“Nanograting Mode”), respectively. We illustrate the utility of our approach by printing two functional devices: (1) a refractive index sensor that can measure the indices of binary mixtures of acetone and methanol at near-infrared wavelengths and (2) a compact polarization beam splitter for polarization control and beam steering in an all-in-fiber system. By combining the superior material properties of glass with the plug-and-play nature of optical fibers, this approach enables promising applications in fields such as fiber sensing, optical microelectromechanical systems (MEMS), and quantum photonics.

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  • 29. Lee, George P
    et al.
    Shi, Yichao
    Lavoie, Ellen
    Daeneke, Torben
    Reineck, Philipp
    Cappel, Ute B
    Huang, David M
    Bach, Udo
    Light-driven transformation processes of anisotropic silver nanoparticles.2013In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 7, no 7, p. 5911-21Article in journal (Refereed)
    Abstract [en]

    The photoinduced formation of silver nanoprisms from smaller silver seed particles in the presence of citrate anions is a classic example of a photomorphic reaction. In this case, light is used as a convenient tool to dynamically manipulate the shape of metal nanoparticles. To date, very little is known about the prevailing reaction mechanism of this type of photoreaction. Here we provide a detailed study of the shape transformation dynamics as a function of a range of different process parameters, such as photon energy and photon flux. For the first time, we provide direct evidence that the photochemical synthesis of silver nanoprisms from spherical seed nanoparticles proceeds via a light-activated two-dimensional coalescence mechanism. On the other hand, we could show that Ostwald ripening becomes the dominant reaction mechanism when larger silver nanoprisms are grown from photochemically synthesized smaller nanoprisms. This two-step reaction proceeds significantly faster and yields more uniform, sharper nanoprisms than the classical one-step photodevelopment process from seeds. The ability to dynamically control nanoparticle shapes and properties with light opens up novel synthesis avenues but also, more importantly, allows one to conceive new applications that exploit the nonstatic character of these nanoparticles and the ability to control and adjust their properties at will in a highly dynamic fashion.

  • 30.
    Lemme, Max C.
    et al.
    Harvard University, Department of Physics.
    Bell, David C.
    Williams, James R.
    Stern, Lewis A.
    Baugher, Britton W. H.
    Jarillo-Herrero, Pablo
    Marcus, Charles M.
    Etching of Graphene Devices with a Helium Ion Beam2009In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 3, no 9, p. 2674-2676Article in journal (Refereed)
    Abstract [en]

    We report on the etching of graphene devices with a helium ion beam, including in situ electrical measurement during lithography. The etching process can be used to nanostructure and electrically isolate different regions In a graphene device, as demonstrated by etching a channel in a suspended graphene device with etched gaps down to about 10 nm. Graphene devices on silicon dioxide (02) substrates etch with lower He ion doses and are found to have a residual conductivity after etching, which we attribute to contamination by hydrocarbons.

  • 31.
    Li, Deyang
    et al.
    Harbin Inst Technol, MIIT Key Lab Crit Mat Technol New Energy Convers, Sch Chem & Chem Engn, Harbin 150001, Peoples R China.;Harbin Inst Technol, Minist Educ, State Key Lab Urban Water Resource & Environm, Harbin 150001, Peoples R China.;Harbin Inst Technol, Minist Educ, Key Lab Microsyst & Microstruct, Harbin 150001, Peoples R China..
    Li, Xiyu
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Zhao, Tianyu
    Harbin Inst Technol, MIIT Key Lab Crit Mat Technol New Energy Convers, Sch Chem & Chem Engn, Harbin 150001, Peoples R China.;Harbin Inst Technol, Minist Educ, State Key Lab Urban Water Resource & Environm, Harbin 150001, Peoples R China.;Harbin Inst Technol, Minist Educ, Key Lab Microsyst & Microstruct, Harbin 150001, Peoples R China..
    Liu, Haichun
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Jiang, Shenlong
    Univ Sci & Technol China, Dept Chem Phys, Hefei Natl Lab Phys Sci Microscale, Hefei 230026, Anhui, Peoples R China..
    Zhang, Qun
    Univ Sci & Technol China, Dept Chem Phys, Hefei Natl Lab Phys Sci Microscale, Hefei 230026, Anhui, Peoples R China..
    Ågren, Hans
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Harbin Inst Technol, MIIT Key Lab Crit Mat Technol New Energy Convers, Sch Chem & Chem Engn, Harbin 150001, Peoples R China.;Harbin Inst Technol, Minist Educ, State Key Lab Urban Water Resource & Environm, Harbin 150001, Peoples R China.;Harbin Inst Technol, Minist Educ, Key Lab Microsyst & Microstruct, Harbin 150001, Peoples R China..
    Chen, Guanying
    Harbin Inst Technol, MIIT Key Lab Crit Mat Technol New Energy Convers, Sch Chem & Chem Engn, Harbin 150001, Peoples R China.;Harbin Inst Technol, Minist Educ, State Key Lab Urban Water Resource & Environm, Harbin 150001, Peoples R China.;Harbin Inst Technol, Minist Educ, Key Lab Microsyst & Microstruct, Harbin 150001, Peoples R China..
    Ultraefficient Singlet Oxygen Generation from Manganese-Doped Cesium Lead Chloride Perovskite Quantum Dots2020In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 14, no 10, p. 12596-12604Article in journal (Refereed)
    Abstract [en]

    Lead halide perovskites hold promise for photo-voltaics, lasers, and light-emitting diode (LED) applications, being known as light-harvesting or -emitting materials. Here we show that colloidal lead halide CsPbCl3 perovskite quantum dots (PQDs), when incorporating divalent manganese (Mn2+) ions, are able to produce spin-paired singlet oxygen molecules with over-unit quantum yield (similar to 1.08) in air conditions. Our mechanistic studies and atomic-level density functional theory calculations endorse an energy-migration-mediated quantum cutting process favoring multiple singlet oxygen generation (MSOG), in which one exciton-activated bulk Mn2+ ion (similar to 2.0 eV) inside the nanocrystal migrates its energy among the Mn2+ sublattice to two surface Mn2+ defect states (similar to 1.0 eV), followed by nonradiative energy transfers to two surrounding oxygen molecules. Moreover, superhydrophobicization of MSOG PQDs through silica-mediated polystyrene encapsulation prevents them from disintegrating in aqueous medium, enabling photodegradation of methyl orange at a rate even higher than that of the canonical titanium oxide photocatalyst. The observation of ultraefficient singlet oxygen generation in PQDs has implications for fields ranging from photodynamic therapy to photocatalytic applications.

  • 32.
    Li, Hailong
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. Department of Physics, AlbaNova University Center, Stockholm University, Stockholm, 10691, Sweden.
    Kruteva, Margarita
    Forschungszentrum Julich, Julich Ctr Neutron Scattering & Biol Matter JCNS, D-52425 Julich, Germany..
    Dulle, Martin
    Forschungszentrum Julich, Julich Ctr Neutron Scattering & Biol Matter JCNS, D-52425 Julich, Germany..
    Wang, Zhen
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Mystek, Katarzyna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Ji, Wenhai
    Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany..
    Pettersson, Torbjörn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Understanding the Drying Behavior of Regenerated Cellulose Gel Beads: The Effects of Concentration and Nonsolvents2022In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 16, no 2, p. 2608-2620Article in journal (Refereed)
    Abstract [en]

    The drying behavior of regenerated cellulose gel beads swollen with different nonsolvents (e.g., water, ethanol, water/ethanol mixtures) is studied in situ on the macroscopic scale with an optical microscope as well as on nanoscale using small-angle/wide-angle X-ray scattering (SAXS/WAXS) techniques. Depending on the cellulose concentration, the structural evolution of beads during drying follows one of three distinct regimes. First, when the cellulose concentration is lower than 0.5 wt %, the drying process comprises three steps and, regardless of the water/ethanol mixture composition, a sharp structural transition corresponding to the formation of a cellulose II crystalline structure is observed. Second, when the cellulose concentration is higher than 5.0 wt %, a two-step drying process is observed and no structural transition occurs for any of the beads studied. Third, when the cellulose concentration is between 0.5 and 5.0 wt %, the drying process is dependent on the nonsolvent composition. A three-step drying process takes place for beads swollen with water/ethanol mixtures with a water content higher than 20%, while a two-step drying process is observed when the water content is lower than 20%. To describe the drying behavior governed by the cellulose concentration and nonsolvent composition, a simplified phase diagram is proposed.

  • 33.
    Li, Hailong
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Kruteva, Margarita
    Forschungszentrum Julich, Julich Ctr Neutron Scattering & Biol Matter JCNS, D-52425 Julich, Germany..
    Mystek, Katarzyna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Dulle, Martin
    Forschungszentrum Julich, Julich Ctr Neutron Scattering & Biol Matter JCNS, D-52425 Julich, Germany..
    Ji, Wenhai
    Forschungszentrum Julich, Julich Ctr Neutron Sci JCNS JCNS 2, D-52425 Julich, Germany..
    Pettersson, Torbjörn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Macro- and microstructural evolution during drying of regenerated cellulose beads2020In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 14, no 6, p. 6774-6784Article in journal (Refereed)
    Abstract [en]

    The macro- and microstructural evolution of water swollen and ethanol swollen regenerated cellulose gel beads have been determined during drying by optical microscopy combined with analytical balance measurements, small-angle X-ray scattering (SAXS), and wide-angle X-ray scattering (WAXS). Two characteristic length scales, which are related to the molecular dimension of cellulose monomer and elongated aggregates of these monomers, could be identified for both types of beads by SAXS. For ethanol swollen beads, only small changes to the structures were detected in both the SAXS and WAXS measurements during the entire drying process. However, the drying of cellulose from water follows a more complex process when compared to drying from ethanol. As water swollen beads dried, they went through a structural transition where elongated structures changed to spherical structures and their dimensions increased from 3.6 to 13.5 nm. After complete drying from water, the nanostructures were characterized as a combination of rodlike structures with an approximate size of cellulose monomers (0.5 nm), and spherical aggregates (13.5 nm) without any indication of heterogeneous meso- or microporosity. In addition, WAXS shows that cellulose II hydrate structure appears and transforms to cellulose II during water evaporation, however it is not possible to determine the degree of crystallinity of the beads from the present measurements. This work sheds lights on the structural changes that occur within regenerated cellulose materials during drying and can aid in the design and application of cellulosic materials as fibers, adhesives, and membranes.

  • 34.
    Li, Jiantong
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Delekta, Szymon Sollami
    Zhang, Panpan
    Yang, Sheng
    Lohe, Martin R.
    Zhuang, Xiaodong
    Feng, Xinliang
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Electronics.
    Scalable Fabrication and Integration of Graphene Microsupercapacitors through Full Inkjet Printing2017In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 11, no 8, p. 8249-8256Article in journal (Refereed)
    Abstract [en]

    A simple full-inkjet-printing technique is developed for the scalable fabrication of graphene-based microsupercapacitors (MSCs) on various substrates. High-performance graphene inks are formulated by integrating the electrochemically exfoliated graphene with a solvent exchange technique to reliably print graphene interdigitated electrodes with tunable geometry and "thickness. Along with the printed polyelectrolyte, poly(4-styrenesulfonic acid), the fully printed graphene-based MSCs attain the highest areal capacitance of similar to 0.7 mF/cm(2), substantially advancing the state-of-art of all-solid-state MSCs with printed graphene electrodes. The full printing solution enables scalable fabrication of MSCs and effective connection of them in parallel and/or in series at various scales. Remarkably, more than 100 devices have been connected to form large-scale MSC arrays as power banks on both silicon wafers and Kapton. Without any extra protection or encapsulation, the MSC arrays can be reliably charged up to 12 V and retain the performance even 8 months after fabrication.

  • 35.
    Li, Lengwan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Chen, Pan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. Beijing Engineering Research Centre of Cellulose and Its Derivatives, School of Materials Science and Engineering, Beijing Institute of Technology, 100081 Beijing, People’s Republic of China.
    Medina, Lilian
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Yang, Lin
    NSLS-II, Brookhaven National Laboratory, Upton, New York 11973, United States.
    Nishiyama, Yoshiharu
    Univ. Grenoble Alpes, CNRS, CERMAV, 38000 Grenoble, France.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Residual Strain and Nanostructural Effects during Drying of Nanocellulose/Clay Nanosheet Hybrids: Synchrotron X-ray Scattering Results2023In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 17, no 16, p. 15810-15820Article in journal (Refereed)
    Abstract [en]

    Cellulose nanofibrils (CNF) with 2D silicate nanoplatelet reinforcement readily form multifunctional composites by vacuum-assisted self-assembly from hydrocolloidal mixtures. The final nanostructure is formed during drying. The crystalline nature of CNF and montmorillonite (MTM) made it possible to use synchrotron X-ray scattering (WAXS, SAXS) to monitor structural development during drying from water and from ethanol. Nanostructural changes in the CNF and MTM crystals were investigated. Changes in the out-of-plane orientation of CNF and MTM were determined. Residual drying strains previously predicted from theory were confirmed in both cellulose and MTM platelets due to capillary forces. The formation of tactoid platelet stacks could be followed. We propose that after filtration, the constituent nanoparticles in the swollen, solid gel already have a “fixed” location, although self-assembly and ordering processes take place during drying.

  • 36. Liu, Guofeng
    et al.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Sheng, Jianhui
    Li, Pei-Zhou
    Ong, Wee Kong
    Phua, Soo Zeng Fiona
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhu, Liangliang
    Zhao, Yanli
    Helicity Inversion of Supramolecular Hydrogels Induced by Achiral Substituents2017In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 11, no 12, p. 11880-11889Article in journal (Refereed)
    Abstract [en]

    Probing the supramolecular chirality of assemblies and controlling their handedness are closely related to the origin of chirality at the supramolecular level and the development of smart materials with desired handedness. However, it remains unclear how achiral residues covalently bonded to chiral amino acids can function in the chirality inversion of supramolecular assemblies. Herein, we report macroscopic chirality and dynamic manipulation of chiroptical activity of hydrogels self-assembled from phenylalanine derivatives, together with the inversion of their handedness achieved solely by exchanging achiral substituents between oligo(ethylene glycol) and carboxylic acid groups. This helicity inversion is mainly induced by distinct stacking mode of the self-assembled building blocks, as collectively confirmed by scanning electron microscopy, circular dichroism, crystallography, and molecular dynamics calculations. Through this straightforward approach, we were able to invert the handedness of helical assemblies by merely exchanging achiral substituents at the terminal of chiral gelators. This work not only presents a feasible strategy to achieve the handedness inversion of helical nanostructures for better understanding of chiral self-assembly process in supramolecular chemistry but also facilities the development of smart materials with controllable handedness in materials science.

  • 37. Lupina, Grzegorz
    et al.
    Kitzmann, Julia
    Costina, Ioan
    Lukosius, Mindaugas
    Wenger, Christian
    Wolff, Andre
    Vaziri, Sam
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Östling, Mikael
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Pasternak, Iwona
    Krajewska, Aleksandra
    Strupinski, Wlodek
    Kataria, Satender
    Gahoi, Amit
    Lemme, Max C.
    Ruhl, Guenther
    Zoth, Guenther
    Luxenhofer, Oliver
    Mehr, Wolfgang
    Residual Metallic Contamination of Transferred Chemical Vapor Deposited Graphene2015In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 9, no 5, p. 4776-4785Article in journal (Refereed)
    Abstract [en]

    Integration of graphene with Si microelectronics is very appealing by offering a potentially broad range of new functionalities. New materials to be integrated with the Si platform must conform to stringent purity standards. Here, we investigate graphene layers grown on copper foils by chemical vapor deposition and transferred to silicon wafers by wet etching and electrochemical delamination methods with respect to residual submonolayer metallic contaminations. Regardless of the transfer method and associated cleaning scheme, time-of-flight secondary ion mass spectrometry and total reflection X-ray fluorescence measurements indicate that the graphene sheets are contaminated with residual metals (copper, iron) with a concentration exceeding 10(13) atoms/cm(2). These metal impurities appear to be partially mobile upon thermal treatment, as shown by depth profiling and reduction of the minority charge carrier diffusion length in the silicon substrate. As residual metallic impurities can significantly alter electronic and electrochemical properties of graphene and can severely impede the process of integration with silicon microelectronics, these results reveal that further progress in synthesis, handling, and cleaning of graphene is required to advance electronic and optoelectronic applications.

  • 38.
    Mittal, Nitesh
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Ansari, Farhan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Department of Materials Science and Engineering, Stanford University, Stanford, CA, United States.
    Gowda, V. Krishne
    KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Brouzet, Christophe
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Chen, Pan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Larsson, Per Tomas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. RISE Bioeconomy, P.O. Box 5604, Stockholm, SwedenRISE Bioeconomy, P.O. Box 5604, Stockholm, Sweden.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Lundell, Fredrik
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Kotov, Nicholas Alexander
    Söderberg, Daniel
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Multiscale Control of Nanocellulose Assembly: Transferring Remarkable Nanoscale Fibril Mechanics to Macroscale Fibers2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 7, p. 6378-6388Article in journal (Refereed)
    Abstract [en]

    Nanoscale building blocks of many materials exhibit extraordinary mechanical properties due to their defect-free molecular structure. Translation of these high mechanical properties to macroscopic materials represents a difficult materials engineering challenge due to the necessity to organize these building blocks into multiscale patterns and mitigate defects emerging at larger scales. Cellulose nanofibrils (CNFs), the most abundant structural element in living systems, has impressively high strength and stiffness, but natural or artificial cellulose composites are 3-15 times weaker than the CNFs. Here, we report the flow-assisted organization of CNFs into macroscale fibers with nearly perfect unidirectional alignment. Efficient stress transfer from macroscale to individual CNF due to cross-linking and high degree of order enables their Young's modulus to reach up to 86 GPa and a tensile strength of 1.57 GPa, exceeding the mechanical properties of known natural or synthetic biopolymeric materials. The specific strength of our CNF fibers engineered at multiscale also exceeds that of metals, alloys, and glass fibers, enhancing the potential of sustainable lightweight high-performance materials with multiscale self-organization.

  • 39.
    Mittal, Nitesh
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Jansson, Ronnie
    KTH, School of Biotechnology (BIO), Protein Technology.
    Widhe, Mona
    KTH, School of Biotechnology (BIO), Protein Technology.
    Benselfelt, Tobias
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Innventia AB, Sweden.
    Håkansson, Karl M. O.
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. Innventia AB, P.O. Box 5604, SE-114 86 Stockholm, Sweden.
    Lundell, Fredrik
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Hedhammar, My
    KTH, School of Biotechnology (BIO), Protein Technology.
    Söderberg, Daniel
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Ultrastrong and Bioactive Nanostructured Bio-Based Composites2017In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 11, no 5, p. 5148-5159Article in journal (Refereed)
    Abstract [en]

    Nature’s design of functional materials relies on smart combinations of simple components to achieve desired properties. Silk and cellulose are two clever examples from nature–spider silk being tough due to high extensibility, whereas cellulose possesses unparalleled strength and stiffness among natural materials. Unfortunately, silk proteins cannot be obtained in large quantities from spiders, and recombinant production processes are so far rather expensive. We have therefore combined small amounts of functionalized recombinant spider silk proteins with the most abundant structural component on Earth (cellulose nanofibrils (CNFs)) to fabricate isotropic as well as anisotropic hierarchical structures. Our approach for the fabrication of bio-based anisotropic fibers results in previously unreached but highly desirable mechanical performance with a stiffness of ∼55 GPa, strength at break of ∼1015 MPa, and toughness of ∼55 MJ m–3. We also show that addition of small amounts of silk fusion proteins to CNF results in materials with advanced biofunctionalities, which cannot be anticipated for the wood-based CNF alone. These findings suggest that bio-based materials provide abundant opportunities to design composites with high strength and functionalities and bring down our dependence on fossil-based resources.

  • 40. Nowakowska, Sylwia
    et al.
    Mazzola, Federico
    Alberti, Mariza N.
    Song, Fei
    Voigt, Tobias
    Nowakowski, Jan
    Wackerlin, Aneliia
    Wackerlin, Christian
    Wiss, Jerome
    Schweizer, W. Bernd
    Broszio, Max
    Polley, Craig
    Leandersson, Mats
    Fatayer, Shadi
    Ivas, Toni
    Baljozovic, Milos
    Mousavi, S. Fatemeh
    Ahsan, Aisha
    Nijs, Thomas
    Popova, Olha
    Zhang, Jun
    Muntwiler, Matthias
    Thilgen, Carlo
    Stohr, Meike
    Pasti, Igor A.
    Skorodumova, Natalia V
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Diederich, Francois
    Wells, Justin
    Jung, Thomas A.
    Adsorbate-Induced Modification of the Confining Barriers in a Quantum Box Array2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 1, p. 768-778Article in journal (Refereed)
    Abstract [en]

    Quantum devices depend on addressable elements, which can be modified separately and in their mutual interaction. Self-assembly at surfaces, for example, formation of a porous (metal-) organic network, provides an ideal way to manufacture arrays of identical quantum boxes, arising in this case from the confinement of the electronic (Shockley) surface state within the pores. We show that the electronic quantum box state as well as the interbox coupling can be modified locally to a varying extent by a selective choice of adsorbates, here C-60, interacting with the barrier. In view of the wealth of differently acting adsorbates, this approach allows for engineering quantum states in on-surface network architectures.

  • 41. Pellarin, Michel
    et al.
    Ramade, Julien
    Rye, Jan Michael
    Bonnet, Christophe
    Broyer, Michel
    Lebeault, Marie-Ange
    Lerme, Jean
    Marguet, Sylvie
    Navarro, Julien R. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Cottancin, Emmanuel
    Fano Transparency in Rounded Nanocube Dimers Induced by Gap Plasmon Coupling2016In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 10, no 12, p. 11266-11279Article in journal (Refereed)
    Abstract [en]

    Homodimers of noble metal nanocubes form model plasmonic systems where the localized plasmon resonances sustained by each particle not only hybridize but also coexist with excitations of a different nature: surface plasmon polaritons confined within the Fabry-Perot cavity delimited by facing cube surfaces (i.e., gap plasmons). Destructive interference in the strong coupling between one of these highly localized modes and the highly radiating longitudinal dipolar plasmon of the dimer is responsible for the formation of a Fano resonance profile and the opening of a spectral window of anomalous transparency for the exciting light. We report on the clear experimental evidence of this effect in the case of 50 nm silver and 160 nm gold nanocube dimers studied by spatial modulation spectroscopy at the single particle level. A numerical study based on a plasmon mode analysis leads us to unambiguously identify the main cavity mode involved in this process and especially the major role played by its symmetry. The Fano depletion dip is red shifted when the gap size is decreasing. It is also blue-shifted and all the more pronounced that the cube edge rounding is large. Combining nanopatch antenna and plasmon hybridization descriptions, we quantify the key role of the face-to-face distance and the cube edge morphology on the spectral profile of the transparency dip.

  • 42. Polley, Craig M.
    et al.
    Buczko, Ryszard
    Forsman, Alexander
    Dziawa, Piotr
    Szczerbakow, Andrzej
    Rechcinski, Rafal
    Kowalski, Bogdan J.
    Story, Tomasz
    Trzyna, Malgorzata
    Bianchi, Marco
    Cabo, Antonija Grubisic
    Hofmann, Philip
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Tjernberg, Oscar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Material Physics, MF.
    Balasubramanian, Thiagarajan
    Fragility of the Dirac Cone Splitting in Topological Crystalline Insulator Heterostructures2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 1, p. 617-626Article in journal (Refereed)
    Abstract [en]

    The "double Dirac cone" 2D topological interface states found on the (001) faces of topological crystalline insulators such as Pb1-xSnxSe feature degeneracies located away from time reversal invariant momenta and are a manifestation of both mirror symmetry protection and valley interactions. Similar shifted degeneracies in 1D interface states have been highlighted as a potential basis for a topological transistor, but realizing such a device will require a detailed understanding of the intervalley physics involved. In addition, the operation of this or similar devices outside of ultrahigh vacuum will require encapsulation, and the consequences of this for the topological interface state must be understood. Here we address both topics for the case of 2D surface states using angle-resolved photoemission spectroscopy. We examine bulk Pb1-xSnxSe(001) crystals overgrown with PbSe, realizing trivial/topological heterostructures. We demonstrate that the valley interaction that splits the two Dirac cones at each (X) over bar is extremely sensitive to atomic-scale details of the surface, exhibiting non-monotonic changes as PbSe deposition proceeds. This includes an apparent total collapse of the splitting for sub-monolayer coverage, eliminating the Lifshitz transition. For a large overlayer thickness we observe quantized PbSe states, possibly reflecting a symmetry confinement mechanism at the buried topological interface.

  • 43.
    Prasad, Amit Kumar
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Sebesta, Jakub
    Uppsala Univ, Dept Phys & Astron, Mat Theory, S-75120 Uppsala, Sweden..
    Esteban-Puyuelo, Raquel
    Uppsala Univ, Dept Phys & Astron, Mat Theory, S-75120 Uppsala, Sweden..
    Maldonado, Pablo
    Uppsala Univ, Dept Phys & Astron, Mat Theory, S-75120 Uppsala, Sweden..
    Ji, Shaozheng
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Sanyal, Biplab
    Uppsala Univ, Dept Phys & Astron, Mat Theory, S-75120 Uppsala, Sweden..
    Granas, Oscar
    Uppsala Univ, Dept Phys & Astron, Mat Theory, S-75120 Uppsala, Sweden..
    Weissenrieder, Jonas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics.
    Nonequilibrium Phonon Dynamics and Its Impact on the Thermal Conductivity of the Benchmark Thermoelectric Material SnSe2023In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 17, no 21, p. 21006-21017Article in journal (Refereed)
    Abstract [en]

    Thermoelectric materials play a vital role in the pursuit of a sustainable energy system by allowing the conversion of waste heat to electric energy. Low thermal conductivity is essential to achieving high-efficiency conversion. The conductivity depends on an interplay between the phononic and electronic properties of the nonequilibrium state. Therefore, obtaining a comprehensive understanding of nonequilibrium dynamics of the electronic and phononic subsystems as well as their interactions is key for unlocking the microscopic mechanisms that ultimately govern thermal conductivity. A benchmark material that exhibits ultralow thermal conductivity is SnSe. We study the nonequilibrium phonon dynamics induced by an excited electron population using a framework combining ultrafast electron diffuse scattering and nonequilibrium kinetic theory. This in-depth approach provides a fundamental understanding of energy transfer in the spatiotemporal domain. Our analysis explains the dynamics leading to the observed low thermal conductivity, which we attribute to a mode-dependent tendency to nonconservative phonon scattering. The results offer a penetrating perspective on energy transport in condensed matter with far-reaching implications for rational design of advanced materials with tailored thermal properties.

  • 44. Quignon, Benoit
    et al.
    Pilkington, Georgia A.
    Thormann, Esben
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Ashfold, Michael N. R.
    Mattia, Davide
    Leese, Hannah
    Davis, Sean A.
    Briscoe, Wuge H.
    Sustained Frictional Instabilities on Nanodomed Surfaces: Stick Slip Amplitude Coefficient2013In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 7, no 12, p. 10850-10862Article in journal (Refereed)
    Abstract [en]

    Understanding the frictional properties of nanostructured surfaces is important because of their increasing application in modem minlaturized devices. In this work, lateral force microscopy was used to study the frictional properties between AFM nanotip and surfaces bearing well-defined ranging from tens to hundreds of nanometers. Our results show that the average lateral force varied linearly with applied load, as described by Amontons' first law of friction, although no direct correlation between the sample topographic properties and their measured friction coeffidents was identified. Furthermore, all the nanodomed textures exhibited pronounced osdllations in the shear traces, similar to the dassic stick slip behavior, under all the shear velocities and load regimes studied. That is, the nanotextured topography led to sustained frictional instabilities, effectively with no contact frictional sliding. The amplitude of the stick slip oscillations, ab was found to correlate with the topographic properties of the surfaces and scale linearly with the applied load. In line with the friction coefficient, we define the slope of this linear plot as the stick slip amplitude coeffident (SSAC). We suggest that such stick slip behaviors are characteristics of surfaces with nanotextures and that such local frictional instabilities have important implications to surface damage and wear. We thus propose that the shear characteristics of the nanodomed surfaces cannot be fully described by the framework of Amontons' laws of friction and that additional parameters (e.g., a, and SSAQ are required, when their friction, lubrication, and wear properties are important considerations in related nanodevices.

  • 45.
    Ram, Farsa
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Garemark, Jonas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Li, Yuanyuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Pettersson, Torbjörn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Functionalized Wood Veneers as Vibration Sensors: Exploring Wood Piezoelectricity and Hierarchical Structure Effects2022In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 16, no 10, p. 15805-15813Article in journal (Refereed)
    Abstract [en]

    Functional wood materials often rely on active additives due to the weak piezoelectric response of wood itself. Here, we chemically modify wood to form functionalized, eco-friendly wood veneer for self-powered vibration sensors. Only the piezoelectricity of the cellulose microfibrils is used, where the drastic improvement comes only from molecular and nanoscale wood structure tuning. Sequential wood modifications (delignification, oxidation, and model fluorination) are performed, and effects on vibration sensing abilities are investigated. Wood veneer piezoelectricity is characterized by the piezoresponse force microscopy mode in atomic force microscopy. Delignification, oxidation, and model fluorination of wood-based sensors provide output voltages of 11.4, 23.2, and 60 mV by facilitating cellulose microfibril deformation. The vibration sensing ability correlates with improved piezoelectricity and increased cellulose deformation, most likely by large, local cell wall bending. This shows that nanostructural wood materials design can tailor the functional properties of wood devices with potential in sustainable nanotechnology. 

  • 46.
    Rosén, Tomas
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA..
    He, HongRui
    SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA..
    Wang, Ruifu
    SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA..
    Zhan, Chengbo
    SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA..
    Chodankar, Shirish
    Brookhaven Natl Lab, Natl Synchrotron Light Source 2, Upton, NY 11793 USA..
    Fall, Andreas
    RISE, S-11486 Stockholm, Sweden..
    Aulin, Christian
    RISE, S-11486 Stockholm, Sweden..
    Larsson, Per A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. RISE, S-11486 Stockholm, Sweden..
    Lindstrom, Tom
    SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA..
    Hsiao, Benjamin S.
    SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA..
    Cross-Sections of Nanocellulose from Wood Analyzed by Quantized Polydispersity of Elementary Microfibrils2020In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 14, no 12, p. 16743-16754Article in journal (Refereed)
    Abstract [en]

    Bio-based nanocellulose has been shown to possess impressive mechanical properties and simplicity for chemical modifications. The chemical properties are largely influenced by the surface area and functionality of the nanoscale materials. However, finding the typical cross-sections of nanocellulose, such as cellulose nanofibers (CNFs), has been a long-standing puzzle, where subtle changes in extraction methods seem to yield different shapes and dimensions. Here, we extracted CNFs from wood with two different oxidation methods and variations in degree of oxidation and high-pressure homogenization. The cross-sections of CNFs were characterized by small-angle X-ray scattering and wide-angle X-ray diffraction in dispersed and freeze-dried states, respectively, where the results were analyzed by assuming that the cross-sectional distribution was quantized with an 18-chain elementary microfibril, the building block of the cell wall. We find that the results agree well with a pseudosquare unit having a size of about 2.4 nm regardless of sample, while the aggregate level strongly depends on the extraction conditions. Furthermore, we find that aggregates have a preferred cohesion of phase boundaries parallel to the (110)-plane of the cellulose fibril, leading to a ribbon shape on average.

  • 47.
    Rönnlund, Daniel
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Xu, Lei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Perols, Anna
    KTH, School of Biotechnology (BIO), Protein Technology.
    Eriksson Karlström, Amelie
    KTH, School of Biotechnology (BIO), Protein Technology.
    Auer, Gert
    Widengren, Jerker
    KTH, School of Engineering Sciences (SCI), Applied Physics, Experimental Biomolecular Physics.
    Multicolor Fluorescence Nanoscopy by Photobleaching: Concept Verification and its Application to Resolve Selective Storage of Proteins in Platelets2014In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 8, no 5, p. 4358-4365Article in journal (Refereed)
    Abstract [en]

    Fluorescence nanoscopy provides means to discernthe finer details of protein localization and interaction in cells by offeringan order of magnitude higher resolution than conventional optical imagingtechniques. However, these super resolution techniques put higher demands onthe optical system as well as on the fluorescent probes, making multicolorfluorescence nanoscopy a challenging task. Here we present a new and simpleprocedure which exploits the photostability and excitation spectra of dyes toincrease the number of simultaneous recordable targets in STED nanoscopy. Weuse this procedure to demonstrate four color STED imaging of platelets with ≤40 nm resolution and low crosstalk. Platelets can selectively store, sequesterand release a multitude of different proteins, and in a manner specific fordifferent physiological and disease states. By applying multicolor nanoscopy tostudy platelets, we can achieve spatial mapping of the protein organizationwith a high resolution, for multiple proteins at the same time and in the samecell. This provides a means to identify specific platelet activation states fordiagnostic purposes and to understand the underlying protein storage andrelease mechanisms. We studied the organization of the pro- and anti-angiogenicproteins VEGF and PF-4 together with fibrinogen and filamentous actin, andfound distinct features in their respective protein localization. Further,colocalization analysis revealed only minor overlap between the proteins VEGFand PF-4 indicating that they have separate storage and release mechanisms,corresponding well with their opposite rules as pro- and anti-angiogenicproteins, respectively.

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    Multicolor-STED
  • 48.
    Saladino, Giovanni
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Vogt, Carmen
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Li, Yuyang
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Shaker, Kian
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Brodin, Bertha
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Svenda, Martin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Hertz, Hans
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Toprak, Muhammet
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Optical and X-ray Fluorescent Nanoparticles for Dual Mode Bioimaging2021In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 15, no 3, p. 5077-5085Article in journal (Refereed)
    Abstract [en]

    Nanoparticle (NP) based contrast agents detectable via different imaging modalities (multimodal properties) provide a promising strategy for noninvasive diagnostics. Core-shell NPs combining optical and X-ray fluorescence properties as bioimaging contrast agents are presented. NPs developed earlier for X-ray fluorescence computed tomography (XFCT), based on ceramic molybdenum oxide (MoO2) and metallic rhodium (Rh) and ruthenium (Ru), are coated with a silica (SiO2) shell, using ethanolamine as the catalyst. The SiO2 coating method introduced here is demonstrated to be applicable to both metallic and ceramic NPs. Furthermore, a fluorophore (Cy5.5 dye) was conjugated to the SiO2 layer, without altering the morphological and size characteristics of the hybrid NPs, rendering them with optical fluorescence properties. The improved biocompatibility of the SiO2 coated NPs without and with Cy5.5 is demonstrated in vitro by Real-Time Cell Analysis (RTCA) on a macrophage cell line (RAW 264.7). The multimodal characteristics of the core-shell NPs are confirmed with confocal microscopy, allowing the intracellular localization of these NPs in vitro to be tracked and studied. In situ XFCT successfully showed the possibility of in vivo multiplexed bioimaging for multitargeting studies with minimum radiation dose. Combined optical and X-ray fluorescence properties empower these NPs as effective macroscopic and microscopic imaging tools.

  • 49.
    Sangghaleh, Fatemeh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Sychugov, Ilya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Yang, Zhenyu
    Veinot, Jonathan G C
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Near-Unity Internal Quantum Efficiency of Luminescent Silicon Nanocrystals with Ligand Passivation.2015In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 9, no 7, p. 7097-7104Article in journal (Refereed)
    Abstract [en]

    Spectrally resolved photoluminescence (PL) decays were measured for samples of colloidal, ligand-passivated silicon nanocrystals. These samples have PL emission energies with peak positions in the range 1.4-1.8 eV and quantum yields of 30-70%. Their ensemble PL decays are characterized by a stretched-exponential decay with a dispersion factor of 0.8, which changes to an almost monoexponential character at fixed detection energies. The dispersion factors and decay rates for various detection energies were extracted from spectrally resolved curves using a mathematical approach that excluded the effect of homogeneous line width broadening. Since nonradiative recombination would introduce a random lifetime variation, leading to a stretched-exponential decay for an ensemble, we conclude that the observed monoexponential decay in size-selected ensembles signifies negligible nonradiative transitions of a similar strength to the radiative one. This conjecture is further supported as extracted decay rates agree with radiative rates reported in the literature, suggesting 100% internal quantum efficiency over a broad range of emission wavelengths. The apparent differences in the quantum yields can then be explained by a varying fraction of "dark" or blinking nanocrystals.

  • 50.
    Shafagh, Reza Zandi
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Vastesson, Alexander
    KTH.
    Guo, Weijin
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Haraldsson, Klas Tommy
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    E-Beam Nanostructuring and Direct Click Biofunctionalization of Thiol–Ene Resist2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 10, p. 9940-9946Article in journal (Refereed)
    Abstract [en]

    Electron beam lithography (EBL) is of major importance for ultraminiaturized biohybrid system fabrication, as it allows combining biomolecular patterning and mechanical structure definition on the nanoscale. Existing methods are limited by multistep biomolecule immobilization procedures, harsh processing conditions that are harmful to sensitive biomolecules, or the structural properties of the resulting protein monolayers or hydrogel-based resists. This work introduces a thiol-ene EBL resist with chemically reactive thiol groups on its native surface that allow the direct and selective "click" immobilization of biomolecules under benign processing conditions. We constructed EBL structured features of size down to 20 nm, and direct functionalized the nanostructures with a sandwich of biotin and streptavidin. The facile combination of polymer nanostructuring with biomolecule immobilization enables mechanically robust biohybrid components of interest for nanoscale biomedical, electronic, photonic, and robotic applications.

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    fulltext
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