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  • 1. Almeida, J. M. P.
    et al.
    Tribuzi, V.
    Fonseca, R. D.
    Otuka, A. J. G.
    Ferreira, P. H. D.
    Mastelaro, V. R.
    Brajato, P.
    Hernandes, A. C.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA. Universidade de São Paulo, Brazil.
    Voss, T.
    Correa, D. S.
    Mendonca, C. R.
    Femtosecond laser processing of glassy and polymeric matrices containing metals and semiconductor nanostructures2013Inngår i: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 35, nr 12, s. 2643-2648Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tailoring properties of materials by femtosecond laser processing has been proposed in the last decade as a powerful approach for technological applications, ranging from optics to biology. Although most of the research output in this field is related to femtosecond laser processing of single either organic or inorganic materials, more recently a similar approach has been proposed to develop advanced hybrid nanomaterials. Here, we report results on the use of femtosecond lasers to process hybrid nanomaterials, composed of polymeric and glassy matrices containing metal or semiconductor nanostructures. We present results on the use of femtosecond pulses to induce Cu and Ag nanoparticles in the bulk of borate and borosilicate glasses, which can be applied for a new generation of waveguides. We also report on 3D polymeric structures, fabricated by two-photon polymerization, containing Au and ZnO nanostructures, with intense two-photon fluorescent properties. The approach based on femtosecond laser processing to fabricate hybrid materials containing metal or semiconductor nanostructures is promising to be exploited for optical sensors and photonics devices.

  • 2. Cardoso, Marcos R.
    et al.
    Martins, Renato J.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Voss, Tobias
    Mendonca, Cleber R.
    Highly hydrophobic hierarchical nanomicro roughness polymer surface created by stamping and laser micromachining2015Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 132, nr 24, artikkel-id 42082Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article describes the design and fabrication of hierarchical nanomicrostructured polymer surfaces with high hydrophobicity. The nanoscale roughness is achieved by stamping a ZnO nanowire film into PDMS. Subsequently, microstructures with different periodicities are created in the stamped PDMS sample by direct laser writing using femtosecond pulses. With this approach, we were able to produce hierarchical surface morphologies, composed of nano and microscale structures that exhibit water contact angles larger than 160 degrees.

  • 3.
    Cavallaro, Sara
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Hååg, Petra
    Sahu, Siddharth S.
    Berisha, Lorenca
    Kaminskyy, Vitaliy O.
    Ekman, Simon
    Lewensohn, Rolf
    Linnros, Jan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Viktorsson, Kristina
    Dev, Apurba
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Multiplexed electrokinetic sensor for detection and therapy monitoring of extracellular vesicles from liquid biopsies of non-small-cell lung cancer patients2021Inngår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 193, s. 113568-113568, artikkel-id 113568Artikkel i tidsskrift (Fagfellevurdert)
  • 4.
    Cavallaro, Sara
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik. Department of Applied Physics;School of Engineering Sciences;KTH Royal Institute of Technology;10691 Stockholm;Sweden.
    Hååg, Petra
    Department of Oncology-Pathology;Karolinska Institutet;17164 Solna;Sweden.
    Viktorsson, Kristina
    Department of Oncology-Pathology;Karolinska Institutet;17164 Solna;Sweden.
    Krozer, Anatol
    Department of Smart Hardware;Division of Digital Systems;Research Institutes of Sweden AB;40014 Gothenburg;Sweden.
    Fogel, Kristina
    Department of Smart Hardware;Division of Digital Systems;Research Institutes of Sweden AB;40014 Gothenburg;Sweden.
    Lewensohn, Rolf
    Department of Oncology-Pathology;Karolinska Institutet;17164 Solna;Sweden;Theme Cancer, Medical Unit Head and Neck, Lung, and Skin Tumors.
    Linnros, Jan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Dev, Apurba
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Comparison and optimization of nanoscale extracellular vesicle imaging by scanning electron microscopy for accurate size-based profiling and morphological analysis2021Inngår i: Nanoscale Advances, E-ISSN 2516-0230, Vol. 3, nr 11, s. 3053-3063Artikkel i tidsskrift (Fagfellevurdert)
  • 5.
    Cavallaro, Sara
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Pevere, Federico
    Uppsala Univ, Angstrom Lab, Dept Elect Engn, S-75121 Uppsala, Sweden..
    Stridfeldt, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Gorgens, Andre
    Karolinska Inst, Dept Lab Med, Clin Res Ctr, S-17177 Stockholm, Sweden.;Evox Therapeut Ltd, Oxford Sci Pk, Oxford OX4 4HG, England.;Univ Duisburg Essen, Univ Hosp Essen, Inst Transfus Med, D-45141 Essen, Germany..
    Paba, Carolina
    Politecn Torino, I-10129 Turin, Italy..
    Sahu, Siddharth S.
    Uppsala Univ, Angstrom Lab, Dept Elect Engn, S-75121 Uppsala, Sweden..
    Mamand, Doste R.
    Karolinska Inst, Dept Lab Med, Clin Res Ctr, S-17177 Stockholm, Sweden..
    Gupta, Dhanu
    Karolinska Inst, Dept Lab Med, Clin Res Ctr, S-17177 Stockholm, Sweden.;Evox Therapeut Ltd, Oxford Sci Pk, Oxford OX4 4HG, England..
    El Andaloussi, Samir
    Karolinska Inst, Dept Lab Med, Clin Res Ctr, S-17177 Stockholm, Sweden.;Evox Therapeut Ltd, Oxford Sci Pk, Oxford OX4 4HG, England..
    Linnros, Jan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Dev, Apurba
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Uppsala Univ, Angstrom Lab, Dept Elect Engn, S-75121 Uppsala, Sweden..
    Multiparametric Profiling of Single Nanoscale Extracellular Vesicles by Combined Atomic Force and Fluorescence Microscopy: Correlation and Heterogeneity in Their Molecular and Biophysical Features2021Inngår i: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 17, nr 14, artikkel-id 2008155Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Being a key player in intercellular communications, nanoscale extracellular vesicles (EVs) offer unique opportunities for both diagnostics and therapeutics. However, their cellular origin and functional identity remain elusive due to the high heterogeneity in their molecular and physical features. Here, for the first time, multiple EV parameters involving membrane protein composition, size and mechanical properties on single small EVs (sEVs) are simultaneously studied by combined fluorescence and atomic force microscopy. Furthermore, their correlation and heterogeneity in different cellular sources are investigated. The study, performed on sEVs derived from human embryonic kidney 293, cord blood mesenchymal stromal and human acute monocytic leukemia cell lines, identifies both common and cell line-specific sEV subpopulations bearing distinct distributions of the common tetraspanins (CD9, CD63, and CD81) and biophysical properties. Although the tetraspanin abundances of individual sEVs are independent of their sizes, the expression levels of CD9 and CD63 are strongly correlated. A sEV population co-expressing all the three tetraspanins in relatively high abundance, however, having average diameters of <100 nm and relatively low Young moduli, is also found in all cell lines. Such a multiparametric approach is expected to provide new insights regarding EV biology and functions, potentially deciphering unsolved questions in this field.

  • 6.
    Dev, Apurba
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Dev Choudhury, Bikash
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Abedin, Ahmad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Anand, Srinivasan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Fabrication of Periodic Nanostructure Assemblies by Interfacial Energy Driven Colloidal Lithography2014Inngår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 24, nr 29, s. 4577-4583Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel interfacial energy driven colloidal lithography technique to fabricate periodic patterns from solution-phase is presented and the feasibility and versatility of the technique is demonstrated by fabricating periodically arranged ZnO nanowire ensembles on Si substrates. The pattern fabrication method exploits different interfaces formed by sol-gel derived ZnO seed solution on a hydrophobic Si surface covered by a monolayer of colloidal silica spheres. While the hydrophobic Si surface prevents wetting by the seed solution, the wedge shaped regions surrounding the contact point between the colloidal particles and the Si substrate trap the solution due to interfacial forces. This technique allows fabrication of uniform 2D micropatterns of ZnO seed particles on the Si substrate. A hydrothermal technique is then used to grow well-defined periodic assemblies of ZnO nanowires. Tunability is demonstrated in the dimensions of the patterns by using silica spheres with different diameters. The experimental data show that the periodic ZnO nanowire assembly suppresses the total reflectivity of bare Si by more than a factor of 2 in the wavelength range 400-1300 nm. Finite-difference time-domain simulations of the wavelength-dependent reflectivity show good qualitative agreement with the experiments. The demonstrated method is also applicable for other materials synthesized by solution chemistry.

  • 7.
    Dev, Apurba
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik. Uppsala University, Sweden.
    Horak, J.
    Kaiser, A.
    Yuan, X.
    Perols, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    Björk, P.
    Karlström, A. E.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    Kleimann, P.
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Electrokinetic effect for molecular recognition: A label-free approach for real-time biosensing2016Inngår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 82, s. 55-63Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a simple and inexpensive method for label-free detection of biomolecules. The method monitors the changes in streaming current in a fused silica capillary as target biomolecules bind to immobilized receptors on the inner surface of the capillary. To validate the concept, we show detection and time response of different protein-ligand and protein-protein systems: biotin-avidin and biotin-streptavidin, barstar-dibarnase and Z domain-immunoglobulin G (IgG). We show that specific binding of these biomolecules can be reliably monitored using a very simple setup. Using sequential injections of various proteins at a diverse concentration range and as well as diluted human serum we further investigate the capacity of the proposed technique to perform specific target detection from a complex sample. We also investigate the time for the signal to reach equilibrium and its dependence on analyte concentration and demonstrate that the current setup can be used to detect biomolecules at a concentration as low as 100 pM without requiring any advanced device fabrication procedures. Finally, an analytical model based on diffusion theory has been presented to explain the dependence of the saturation time on the analyte concentration and capillary dimensions and how reducing length and inner diameter of the capillary is predicted to give faster detection and in practice also lower limit of detection.

  • 8.
    Dev Choudhury, Bikash
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Abedin, Ahmad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Sanatinia, Reza
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Anand, Srinivasan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Silicon micro-structure and ZnO nanowire hierarchical assortments for light management2013Inngår i: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 3, nr 8, s. 1039-1048Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present fabrication and optical characterization of Si microstructure-ZnO nanowire (NWs) hierarchical structures for light management. Random and periodic hierarchical structures constituting Si micro pillar or micro pyramid arrays with overgrown ZnO NWs have been fabricated. Inexpensive colloidal lithography in combination with dry and wet chemical etching is used to fabricate Si microstructures, and ZnO NWs are grown by hydrothermal synthesis. The periodic Si micro pyramid-ZnO NWs hierarchical structure shows broadband antireflection with average reflectance as low as 2.5% in the 300-1000 nm wavelength range. A tenfold enhancement in Raman intensity is observed in this structure compared to planar Si sample. These hierarchical structures with enriched optical properties and high surface to volume ratio are promising for photovoltaic (PV) and sensor applications.

  • 9. Fonseca, R. D.
    et al.
    Correa, D. S.
    Paris, E. C.
    Tribuzi, V.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Voss, T.
    Aoki, P. H. B.
    Constantino, C. J. L.
    Mendonca, C. R.
    Fabrication of zinc oxide nanowires/polymer composites by two-photon polymerization2014Inngår i: Journal of Polymer Science Part B: Polymer Physics, ISSN 0887-6266, E-ISSN 1099-0488, Vol. 52, nr 4, s. 333-337Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present an approach to fabricate ZnO nanowires/polymer composite into three-dimensional microstructures, based on two-photon polymerization direct laser writing, a fabrication method that allows submicrometric spatial resolution. The structural integrity of the structures was inferred by scanning electron microscopy, while the presence and distribution of ZnO nanowires was investigated by energy dispersive X-ray, Raman spectroscopy, and X-ray diffraction. The optical properties of the produced composite microstructures were verified by imaging the characteristic ZnO emission using a fluorescence microscope. Hence, such approach can be used to develop composite microstructures containing ZnO nanowires aiming at technological applications.

  • 10. Hou, D.
    et al.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Halvledarmaterial, HMA.
    Frank, K.
    Rosenauer, A.
    Voss, T.
    Oxygen-controlled photoconductivity in ZnO nanowires functionalized with colloidal CdSe quantum dots2012Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, nr 36, s. 19604-19610Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    ZnO nanowire arrays were functionalized with colloidal CdSe quantum dots stabilized by 3-mercaptopropionic acid to form hybrid devices. The photoconductivity of the nanowire/quantum-dot devices was studied under selective photoexcitation of the quantum dots, and it was found that the dynamics strongly depend on the gas environment. Desorption of surface oxygen from both the ZnO nanowires and the CdSe quantum dots, activated by electron tunnelling between the nanowires and the quantum dots, is found to be the dominating process that determines the dynamics of the photoconductivity in the hybrid nanowire/quantum-dot devices.

  • 11.
    Metaferia, Wondwosen
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Kataria, Himanshu
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Junesand, Carl
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Sun, Yanting
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Anand, Srinivasan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Tommila, Juha
    Pozina, Galia
    Hultman, Lars
    Guina, Mircea
    Niemi, Tapio
    Lourdudoss, Sebastian
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    High quality InP nanopyramidal frusta on Si2014Inngår i: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 16, nr 21, s. 4624-4632Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanosized octagonal pyramidal frusta of indium phosphide were selectively grown at circular hole openings on a silicon dioxide mask deposited on indium phosphide and indium phosphide pre-coated silicon substrates. The eight facets of the frusta were determined to be {111} and {110} truncated by a top (100) facet. The size of the top flat surface can be controlled by the diameter of the openings in the mask and the separation between them. The limited height of the frusta is attributed to kinetically controlled selective growth on the (100) top surface. Independent analyses with photoluminescence, cathodoluminescence and scanning spreading resistance measurements confirm certain doping enrichment in the frustum facets. This is understood to be due to crystallographic orientation dependent dopant incorporation. The blue shift from the respective spectra is the result of this enrichment exhibiting the Burstein-Moss effect. Very bright panchromatic cathodoluminescence images indicate that the top surfaces of the frusta are free from dislocations. The good optical and morphological quality of the nanopyramidal frusta indicates that the fabrication method is very attractive for the growth of site-, shape-, and number-controlled semiconductor quantum dot structures on silicon for nanophotonic applications.

  • 12.
    Naureen, Shagufta
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Halvledarmaterial, HMA.
    Shahid, Naeem
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Halvledarmaterial, HMA.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Halvledarmaterial, HMA.
    Anand, Srinivasan
    Generation of substrate free III-V nanodisksfrom user-defined multilayer nanopillar arraysArtikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    High material quality InP-based multilayer nanopillar (NP) arrays are fabricated using a combination of self-assembly of silica particles for mask generation and dry etching. In particular, the NP arrays are made from user-defined epitaxial multi-layer stacks with specific materials and layer thickness. Additional degree of flexibility in the structures is obtained by changing the lateral diameters of the NP multi-layer stacks. Pre-defined NP arrays made in InGaAsP/InP and InGaAs/InP NPs are then used to generate substrate-free nanodisks of a chosen material from the stack by selective etching. A soft-stamping method is demonstrated to transfer the generated nanodisks with arbitrary densities onto Si. It is shown that the transferred nanodisks retain their smooth surface morphologies and their designed geometrical dimensions. Both InP and InGaAsP nanodisks display excellent photo-luminescence properties, with line-widths comparable to unprocessed reference epitaxial layers of similar composition. The multilayer NP arrays are potentially attractive for broad-band absorption in third-generation solar-cells. The high optical quality, substrate-free InP and InGaAsP nanodisks on Si offer a new path to explore alternative ways to integrate III-V on Si by bonding nanodisks to Si. The method also has the advantage of re-usable III-V substrates for subsequent layer growth.

  • 13.
    Naureen, Shagufta
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Shahid, Naeem
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Anand, Srinivasan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Halvledarmaterial, HMA.
    Generation of substrate-free III-V nanodisks from user-defined multilayer nanopillar arrays for integration on Si2013Inngår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 24, nr 22, s. 225301-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High material quality InP-based multilayer nanopillar (NP) arrays are fabricated using a combination of self-assembly of silica particles for mask generation and dry etching. In particular, the NP arrays are made from user-defined epitaxial multilayer stacks with specific materials and layer thicknesses. An additional degree of flexibility in the structures is obtained by changing the lateral diameters of the NP multilayer stacks. Pre-defined NP arrays made from InGaAsP/InP and InGaAs/InP NPs are then used to generate substrate-free nanodisks of a chosen material from the stack by selective etching. A soft-stamping method is demonstrated to transfer the generated nanodisks with arbitrary densities onto Si. The transferred nanodisks retain their smooth surface morphologies and their designed geometrical dimensions. Both InP and InGaAsP nanodisks display excellent photoluminescence properties, with line-widths comparable to unprocessed reference epitaxial layers of similar composition. The multilayer NP arrays are potentially attractive for broad-band absorption in third-generation solar cells. The high optical quality, substrate-free InP and InGaAsP nanodisks on Si offer a new path to explore alternative ways to integrate III-V on Si by bonding nanodisks to Si. The method also has the advantage of re-usable III-V substrates for subsequent layer growth.

  • 14.
    Parmeggiani, Matteo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Dev, Apurba
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Uppsala University, Uppsala, Sweden.
    Björk, P.
    Linnros, Jan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Electrokinetic-assisted gating in a microfluidic integrated Si nanoribbon ion sensor for enhanced sensitivity2018Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 262, s. 974-981Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using the electrokinetic principle, we demonstrate a novel approach to modulate the response of an ion sensitive silicon-nanoribbon field-effect-transistor, effectively manipulating the device sensitivity to a change in surface potential. By using the streaming potential effect we show that the changes in the surface potential induced by e.g. a pH change can be accurately manipulated in a microfluidic-integrated chip leading to an enhanced response. By varying the flow velocity and the biasing condition along the microfluidic channel, we further demonstrate that the pH response from such a device can also be suppressed or even reversed as a function of the flow velocity and the biasing configuration. Experiments performed with different pH buffer shows that the sensor response can be enhanced/suppressed by several times in magnitude simply by using the streaming potential effects. A mathematical description is also presented for qualitative assessment of the electrokinetic influence on the gate terminal under different biasing condition. The approach presented here shows the prospect to exploit the electrokinetic modulation for developing highly sensitive nanoscale biosensors. 

  • 15. Richters, J. -P
    et al.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF. University of Bremen, Germany.
    Ronning, C.
    Gutowski, J.
    Voss, T.
    Functional ZnO/polymer core-shell nanowires fabricated by oxidative chemical vapour deposition2014Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 47, nr 39, artikkel-id 394004Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Functional ZnO-nanowire/polymer core-shell heterostructures were realized using oxidative chemical vapour deposition (oCVD). This dry and versatile technique allows uniform coating of semiconductor nanowires with polymers and simultaneous doping control of the shell. Here, 100 nm thick, p-doped shells of poly(3,4-ethylenedioxythiophene) (PEDOT) were deposited around n-conductive ZnO nanowires. Energy-dispersive x-ray spectroscopy confirms the incorporation of Br dopants into the PEDOT shell, and the resulting p-conductivity of the polymer shell is demonstrated by electrical measurements on nanowire arrays. Photoluminescence spectroscopy points to reactions of Br with the ZnO surface but proves that the nanowires show only little degradation of their optical properties.

  • 16.
    Sahu, Siddharth S.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Gevari, Moein T.
    Uppsala Univ, Dept Elect Engn, Div Solid State Elect, S-75121 Uppsala, Sweden..
    Nagy, Abel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    Gestin, Maxime
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    Haag, Petra
    Karolinska Inst, Dept Oncol Pathol, S-17164 Stockholm, Sweden..
    Lewensohn, Rolf
    Karolinska Inst, Dept Oncol Pathol, S-17164 Stockholm, Sweden.;Karolinska Univ Hosp, Thorac Oncol Ctr, Med Unit Head & Neck Lung & Skin Tumors, Theme Canc, S-17164 Solna, Sweden..
    Viktorsson, Kristina
    Karolinska Inst, Dept Oncol Pathol, S-17164 Stockholm, Sweden..
    Eriksson Karlström, Amelie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    Dev, Apurba
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Uppsala Univ, Dept Elect Engn, Div Solid State Elect, S-75121 Uppsala, Sweden..
    Multi-marker profiling of extracellular vesicles using streaming current and sequential electrostatic labeling2023Inngår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 227, artikkel-id 115142Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High heterogeneity in the membrane protein expression of small extracellular vesicles (sEVs) means that bulk methods relying on antibody-based capture for expression analysis have a drawback that each type of antibody may capture a different sub-population. An improved approach is to capture a representative sEV population, without any bias, and then perform a multiplexed protein expression analysis on this population. However, such a possibility has been largely limited to fluorescence-based methods. Here, we present a novel electrostatic labelling strategy and a microchip-based all-electric method for membrane protein analysis of sEVs. The method allows us to profile multiple surface proteins on the captured sEVs using alternating charge labels. It also permits the comparison of expression levels in different sEV-subtypes. The proof of concept was tested by capturing sEVs both non-specifically (unbiased) as well as via anti-CD9 capture probes (biased), and then profiling the expression levels of various surface proteins using the charge labelled antibodies. The method is the first of its kind, demonstrating an all-electrical and microchip based method that allows for unbiased analysis of sEV membrane protein expression, comparison of expression levels in different sEV subsets, and fractional estimation of different sEV sub-populations. These results were also validated in parallel using a single-sEV fluorescence technique.

  • 17.
    Sahu, Siddharth Sourabh
    et al.
    Uppsala Univ, Dept Elect Engn, Angstrom Lab, S-75121 Uppsala, Sweden..
    Cavallaro, Sara
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Haag, Petra
    Karolinska Inst, Dept Oncol Pathol, S-17164 Stockholm, Sweden..
    Nagy, Abel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    Eriksson Karlström, Amelie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    Lewensohn, Rolf
    Karolinska Inst, Dept Oncol Pathol, S-17164 Stockholm, Sweden.;Karolinska Univ Hosp, Theme Canc, Patient Area Head & Neck Lung & Skin, S-17164 Solna, Sweden..
    Viktorsson, Kristina
    Karolinska Inst, Dept Oncol Pathol, S-17164 Stockholm, Sweden..
    Linnros, Jan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Dev, Apurba
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik. Uppsala Univ, Dept Elect Engn, Angstrom Lab, S-75121 Uppsala, Sweden..
    Exploiting Electrostatic Interaction for Highly Sensitive Detection of Tumor-Derived Extracellular Vesicles by an Electrokinetic Sensor2021Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 13, nr 36, s. 42513-42521Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present an approach to improve the detection sensitivity of a streaming current-based biosensor for membrane protein profiling of small extracellular vesicles (sEVs). The experimental approach, supported by theoretical investigation, exploits electrostatic charge contrast between the sensor surface and target analytes to enhance the detection sensitivity. We first demonstrate the feasibility of the approach using different chemical functionalization schemes to modulate the zeta potential of the sensor surface in a range -16.0 to -32.8 mV. Thereafter, we examine the sensitivity of the sensor surface across this range of zeta potential to determine the optimal functionalization scheme. The limit of detection (LOD) varied by 2 orders of magnitude across this range, reaching a value of 4.9 x 10(6) particles/mL for the best performing surface for CD9. We then used the optimized surface to profile CD9, EGFR, and PD-L1 surface proteins of sEVs derived from non-small cell lung cancer (NSCLC) cell-line H1975, before and after treatment with EGFR tyrosine kinase inhibitors, as well as sEVs derived from pleural effusion fluid of NSCLC adenocarcinoma patients. Our results show the feasibility to monitor CD9, EGFR, and PD-L1 expression on the sEV surface, illustrating a good prospect of the method for clinical application.

  • 18.
    Sahu, Siddharth Sourabh
    et al.
    Uppsala Univ, Dept Elect Engn, Angstrom Lab, Uppsala, Sweden..
    Stiller, Christiane
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Proteinvetenskap.
    Paz Gomero, Elizabeth
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    Nagy, Abel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Proteinvetenskap.
    Linnros, Jan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Dev, Apurba
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik. Uppsala Univ, Dept Elect Engn, Angstrom Lab, Uppsala, Sweden..
    Electrokinetic sandwich assay and DNA mediated charge amplification for enhanced sensitivity and specificity2021Inngår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 176, artikkel-id 112917Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An electrical immuno-sandwich assay utilizing an electrokinetic-based streaming current method for signal transduction is proposed. The method records the changes in streaming current, first when a target molecule binds to the capture probes immobilized on the inner surface of a silica micro-capillary, and then when the detection probes interact with the bound target molecules on the surface. The difference in signals in these two steps constitute the response of the assay, which offers better target selectivity and a linear concentration dependent response for a target concentration within the range 0.2-100 nM. The proof of concept is demonstrated by detecting different concentrations of Immunoglobulin G (IgG) in both phosphate buffered saline (PBS) and spiked in E. coli cell lysate. A superior target specificity for the sandwich assay compared to the corresponding direct assay is demonstrated along with a limit of detection of 90 pM in PBS. The prospect of improving the detection sensitivity was theoretically analysed, which indicated that the charge contrast between the target and the detection probe plays a crucial role in determining the signal. This aspect was then experimentally validated by modulating the zeta potential of the detection probe by conjugating negatively charged DNA oligonucleotides. The length of the conjugated DNA was varied from 5 to 30 nucleotides, altering the zeta potential of the detection probe from -9.3 +/- 0.8 mV to -20.1 +/- 0.9 mV. The measurements showed a clear and consistent enhancement of detection signal as a function of DNA lengths. The results presented here conclusively demonstrate the role of electric charge in detection sensitivity as well as the prospect for further improvement. The study therefore is a step forward in developing highly selective and sensitive electrokinetic assays for possible application in clinical investigations.

  • 19. Schneider, A.
    et al.
    Sebald, K.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Halvledarmaterial, HMA.
    Frank, K.
    Rosenauer, A.
    Voss, T.
    Towards optical hyperdoping of binary oxide semiconductors2013Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, nr 14, s. 143512-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Surface structuring with ultrashort laser pulses is of high interest as a scalable doping technique as well as for surface nanostructuring applications. By depositing a layer of antimony before the irradiation of ZnO, we were able to incorporate a large quantity of Sb atoms into the single crystalline region of the laser modified surface for potential p-type doping. We have studied the incorporation of antimony and the material properties of laser-induced periodic surface structures (LIPSS) on c-plane ZnO upon femtosecond laser processing at two different peak fluences. We observe high spatial frequency LIPSS with structure periods from 200-370 nm and low spatial frequency LIPSS with periods of 600-700 nm. At a fluence of 0.8 J/cm(2), close the ablation threshold of ZnO, the LIPSS are single crystalline except for a few nanometers of amorphous material. At a peak laser fluence of 3.1 J/cm(2), they consist of polycrystalline and single crystalline ZnO areas. However, the polycrystalline part dominates with a thickness of about 500 nm.

  • 20.
    Stridfeldt, Fredrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Cavallaro, Sara
    Massachusetts Gen Hosp, Ctr Canc Res, Boston, MA 02129 USA..
    Haag, Petra
    Karolinska Inst, Dept Oncol Pathol, S-17164 Solna, Sweden..
    Lewensohn, Rolf
    Karolinska Inst, Dept Oncol Pathol, S-17164 Solna, Sweden.;Karolinska Univ Hosp, Thorac Oncol Ctr, Med Unit Head & Neck, Theme Canc, SE-17164 Solna, Sweden..
    Linnros, Jan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Viktorsson, Kristina
    Karolinska Inst, Dept Oncol Pathol, S-17164 Solna, Sweden..
    Dev, Apurba
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Uppsala Univ, Dept Elect Engn, Angstromslab, Box 534, SE-75121 Uppsala, Sweden..
    Analyses of single extracellular vesicles from non-small lung cancer cells to reveal effects of epidermal growth factor receptor inhibitor treatments2023Inngår i: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 259, artikkel-id 124553Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Precision cancer medicine has changed the treatment landscape of non-small cell lung cancer (NSCLC) as illustrated by the introduction of tyrosine kinase inhibitors (TKIs) towards mutated epidermal growth factor receptor (EGFR). However, as responses to EGFR-TKIs are heterogenous among NSCLC patients, there is a need for ways to early monitor changes in treatment response in a non-invasive way e.g., in patient's blood samples. Recently, extracellular vesicles (EVs) have been identified as a source of tumor biomarkers which could improve on non-invasive liquid biopsy-based diagnosis of cancer. However, the heterogeneity in EVs is high. Putative biomarker candidates may be hidden in the differential expression of membrane proteins in a subset of EVs hard to identify using bulk techniques. Using a fluorescence-based approach, we demonstrate that a single-EV tech-nique can detect alterations in EV surface protein profiles. We analyzed EVs isolated from an EGFR-mutant NSCLC cell line, which is refractory to EGFR-TKIs erlotinib and responsive to osimertinib, before and after treatment with these drugs and after cisplatin chemotherapy. We studied expression level of five proteins; two tetraspanins (CD9, CD81), and three markers of interest in lung cancer (EGFR, programmed death-ligand 1 (PD-L1), human epidermal growth factor receptor 2 (HER2)). The data reveal alterations induced by the osimertinib treatment compared to the other two treatments. These include the growth of the PD-L1/HER2-positive EV population, with the largest increase in vesicles exclusively expressing one of the two proteins. The expression level per EV decreased for these markers. On the other hand, both the TKIs had a similar effect on the EGFR-positive EV population.

  • 21.
    Yang, Yupeng
    et al.
    Division of Solid-State Electronics, Department of Electrical Engineering, The Ångström Laboratory, Uppsala University, SE-751 03 Uppsala, Sweden.
    Dev, Apurba
    Division of Solid-State Electronics, Department of Electrical Engineering, The Ångström Laboratory, Uppsala University, SE-751 03 Uppsala, Sweden.
    Sychugov, Ilya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik. Division of Photonics, Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Hägglund, Carl
    Division of Solar Cell Technology, Department of Materials Science and Engineering, The Ångström Laboratory, Uppsala University, SE-751 03 Uppsala, Sweden.
    Zhang, Shi Li
    Division of Solid-State Electronics, Department of Electrical Engineering, The Ångström Laboratory, Uppsala University, SE-751 03 Uppsala, Sweden.
    Plasmon-Enhanced Fluorescence of Single Quantum Dots Immobilized in Optically Coupled Aluminum Nanoholes2023Inngår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 14, nr 9, s. 2339-2346Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fluorescence-based optical sensing techniques have continually been explored for single-molecule detection targeting myriad biomedical applications. Improving signal-to-noise ratio remains a prioritized effort to enable unambiguous detection at single-molecule level. Here, we report a systematic simulation-assisted optimization of plasmon-enhanced fluorescence of single quantum dots based on nanohole arrays in ultrathin aluminum films. The simulation is first calibrated by referring to the measured transmittance in nanohole arrays and subsequently used for guiding their design. With an optimized combination of nanohole diameter and depth, the variation of the square of simulated average volumetric electric field enhancement agrees excellently with that of experimental photoluminescence enhancement over a large range of nanohole periods. A maximum 5-fold photoluminescence enhancement is statistically achieved experimentally for the single quantum dots immobilized at the bottom of simulation-optimized nanoholes in comparison to those cast-deposited on bare glass substrate. Hence, boosting photoluminescence with optimized nanohole arrays holds promises for single-fluorophore-based biosensing.

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