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  • 51. Wang, Hui
    et al.
    Lee, Irene H.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    A general method to determine ionization constants of responsive polymer thin films2012In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 365, no 1, p. 178-183Article in journal (Refereed)
    Abstract [en]

    A general method has been developed to determine the ionization constants of polymer thin films based on the stimuli-responsiveness of the polymer. Robust polymer films were fabricated on silicon wafers and gold slides using perfluorophenyl azide (PFPA) as the coupling agent. The ionization constants were measured by a number of techniques including ellipsometry, dynamic contact angle goniometry, and surface plasmon resonance imaging (SPRi). Using poly(4-vinylpyridine) (P4VP) as the model system. P4VP thin films were fabricated and the ionization constants of the films were measured taking advantage of the pH responsive property of the polymer. The pK(a) determined by ellipsometry, similar to 4.0, reflects the swelling of the polymer film in response to pH. The pKa value calculated from the dynamic contact angle measurements, similar to 5.0, relies on the change in hydrophilicity/hydrophobicity of the films as the polymer undergoes protonation/deprotonation. The pK(a) value measured by SPRi, similar to 4.9, monitors in situ the change of refractive index of the polymer thin film as it swells upon protonation. This was the first example where SPRi was used to measure the ionization constants of polymers.

  • 52. Wang, Hui
    et al.
    Li, Liling
    Tong, Qi
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Evaluation of Photochemically Immobilized Poly(2-ethyl-2-oxazoline) Thin Films as Protein-Resistant Surfaces2011In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 3, no 9, p. 3463-3471Article in journal (Refereed)
    Abstract [en]

    Poly(2-ethyl-2-oxazoline) (PEOX) of various molecular weights were covalently immobilized on silicon wafers and gold slides to form protein-resistant surfaces via a fast and general photocoupling chemistry based on the CH insertion reaction of light-activated perfluorophenyl azide (PFPA). The thicknesses of the immobilized PEOX films ranged from 23 to 80 angstrom for molecular weight of 5000 to 500 000, and the grafting density reached 3.2 x 10(-3) A(-2) for PEOX 5000. The protein-resistant property of the films was studied using bovine serum albumin (BSA) by fluorescence imaging, ellipsometry, and surface plasmon resonance imaging (SPRi). The fluorescence imaging and ellipsometry studies showed the largest amount of BSA adsorbed on PEOX 5000 and the smallest on PEOX 500 000. This was consistent with the kinetic analysis of BSA adsorption by SPRi showing that PEOX 5000 exhibited the fastest association rate and the slowest dissociation rate whereas PEOX 500 000 had the slowest association rate and the fastest dissociation rate. The PEOX film was then applied in the fabrication of carbohydrate microarrays to reduce the nonspecific adsorption of lectins and thus the background noises. Results showed that the microarray signals were significantly enhanced when the PEOX film was used.

  • 53. Wang, Hui
    et al.
    Ren, Jin
    Hlaing, Aye
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Fabrication and anti-fouling properties of photochemically and thermally immobilized poly(ethylene oxide) and low molecular weight poly(ethylene glycol) thin films2011In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 354, no 1, p. 160-167Article in journal (Refereed)
    Abstract [en]

    Poly(ethylene oxide) (PEO) and low molecular weight poly(ethylene glycol) (PEG) were covalently immobilized on silicon wafers and gold films by way of the CH insertion reaction of perfluorophenyl azides (PFPAs) by either photolysis or thermolysis. The immobilization does not require chemical derivatization of PEO or PEG, and polymers of different molecular weights were successfully attached to the substrate to give uniform films. Microarrays were also generated by printing polymer solutions on PFPA-functionalized wafer or Au slides followed by light activation. For low molecular weight PEG, the immobilization was highly dependent on the quality of the film deposited on the substrate. While the spin-coated and printed PEG showed poor immobilization efficiency, thermal treatment of the PEG melt on PFPA-functionalized surfaces resulted in excellent film quality, giving, for example, a grafting density of 9.2 x 10(-4) angstrom(-2) and an average distance between grafted chains of 33 angstrom for PEG 20,000. The anti-fouling property of the films was evaluated by fluorescence microscopy and surface plasmon resonance imaging (SPRi). Low protein adsorption was observed on thermally-immobilized PEG whereas the photoimmobilized PEG showed increased protein adsorption. In addition, protein arrays were created using polystyrene (PS) and PEG based on the differential protein adsorption of the two polymers.

  • 54. Wang, Huibin
    et al.
    Zhang, Yiming
    Yuan, Xun
    Chen, Yi
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    A Universal Protocol for Photochemical Covalent Immobilization of Intact Carbohydrates for the Preparation of Carbohydrate Microarrays2011In: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 22, no 1, p. 26-32Article in journal (Refereed)
    Abstract [en]

    A universal photochemical method has been established for the immobilization of intact carbohydrates and their analogues, and for the fabrication of carbohydrate microarrays. The method features the use of perfluorophenyl azide (PFPA)-modified substrates and the photochemical reaction of surface azido groups with printed carbohydrates. Various aldoses, ketoses, nonreducing sugars such as alditols, and their derivatives can be directly arrayed on the PFPA-modified chips. The lectin-recognition ability of arrayed mannose, glucose, and their oligo- and polysaccharides were confirmed using surface-plasmon resonance imaging and laser-induced fluorescence imaging.

  • 55. Wang, Xiaohua
    et al.
    Wang, Xin
    Fernandez, Rodolfo
    Ocola, Leonidas
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    La Rosa, Andres
    Electric-Field-Assisted Dip-Pen Nanolithography on Poly(4-vinylpyridine) (P4VP) Thin Films2010In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 2, no 10, p. 2904-2909Article in journal (Refereed)
    Abstract [en]

    Dip-pen nanolithography (DPN) has attracted increased attention for its ability to generate nanometer-scale patterns on solid surface using an “ink”-coated atomic force microscope (AFM) tip. In contrast to this conventional anchoring-molecules procedure, nanopatterns can also be created by triggering the structural response of the proper substrate. In one approach, the delivery of acidic buffer from the tip into a poly(4-vinylpyridine) (P4VP) thin film (while the tip is being laterally moved, in a raster fashion, along a preprogrammed pattern) leads to the polymer swelling in response to the local protonation. This practice, however, has suffered from a lack of consistency due to the potentially many factors influencing the pattern formation. Herein we report that a more reliable strategy for well controlling the protonation process results when applying an electric held between the AFM tip and the sample. We demonstrate the improved capabilities of the electric-field-assisted DPN method towards reproducibly and reliably fabricating nanostructures by taking advantage of the responsive characteristics (i.e. swelling) of P4VP. Our work includes a systematic study of pattern fabrication under different patterning parameters (mainly the applied bias and contact force) and, very important, provides evidence of the reversible characteristic of the pattern formation process.

  • 56. Wang, Xin
    et al.
    Liu, Li-Hong
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Engineering Nanomaterial Surfaces for Biomedical Applications2009In: Experimental biology and medicine (Maywood, N.J.: Print), ISSN 1535-3702, E-ISSN 1535-3699, Vol. 234, no 10, p. 1128-1139Article in journal (Refereed)
    Abstract [en]

    Nanomaterials, possessing unique physical and chemical properties, have attracted much interest and generated wide varieties of applications. Recent investigations of functionalized nanomaterials have expanded into the biological area, providing a versatile platform in biomedical applications such as biomolecular sensing, biological imaging, drug delivery and disease therapy. Bio-functions and bio-compatibility of nanomaterials are realized by introducing synthetic ligands or natural biomolecules onto nanomaterials, and combining ligand-receptor biological interactions with intrinsic nanomaterial properties. Common strategies of engineering nanomaterial surfaces involve physisorption or chemisorption of desired ligands. We developed a phollochemically initiated surface coupling chemistry, bringing versatility and simplicity to nanomaterial functionalization. The method was applied to attach underivatized carbohydrates efficiently on gold and iron oxide nanoparticles, and the resulting glyconanoparticles were successfully used as a sensitive biosensing system probing specific interactions between carbohydrates and proteins as well as bacteria. Exp Biol Med 234:1128-1139, 2009

  • 57. Wang, Xin
    et al.
    Matei, Elena
    Deng, Lingquan
    Koharudin, Leonardus
    Gronenborn, Angela M.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    Sensing lectin-glycan interactions using lectin super-microarrays and glycans labeled with dye-doped silica nanoparticles2013In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 47, p. 258-264Article in journal (Refereed)
    Abstract [en]

    A new microarray platform, based on lectin super-microarrays and glycans labeled with dye-doped nanoparticles, has been developed to study glycan-lectin interactions. Glycan ligands were conjugated onto fluorescein-doped silica nanoparticles (FSNPs) using a general photocoupling chemistry to afford FSNP-labeled glycan probes. Lectins were printed on epoxy slides in duplicate sets to generate lectin super-microarrays where multiple assays could be carried out simultaneously in each lectin microarray. Thus, the lectin super-microarray was treated with FSNP-labeled glycans to screen for specific binding pairs. Furthermore, a series of ligand competition assays were carried out on a single lectin super-microarray to generate the dose-response curve for each glycan-lectin pair, from which the apparent affinity constants were obtained. Results showed 4-7 orders of magnitude increase in affinity over the free glycans with the corresponding lectins. Thus, the glycan epitope structures having weaker affinity than the parent glycans could be readily identified and analyzed from the lectin super-microarrays.

  • 58. Wang, Xin
    et al.
    Matei, Elena
    Deng, Lingquan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Gronenborn, Angela M.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Multivalent glyconanoparticles with enhanced affinity to the anti-viral lectin Cyanovirin-N2011In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, no 30, p. 8620-8622Article in journal (Refereed)
    Abstract [en]

    Low-mannose (LM) structures were coupled to gold nanoparticles (Au NPs) to amplify the affinity of LMs with Cyanovirin-N (CV-N) lectins and to study the structures of CV-N variants CVN(Q50C) and CVN(MutDB).

  • 59. Wang, Xin
    et al.
    Matei, Elena
    Gronenborn, Angela M.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Direct Measurement of Glyconanoparticles and Lectin Interactions by Isothermal Titration Calorimetry2012In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 84, no 10, p. 4248-4252Article in journal (Refereed)
    Abstract [en]

    Glyconanomaterials have shown high potential in applications including bioanalysis and nanomedicine. Here, a quantitative analytical technique, based on isothermal titration calorimetry, was developed to characterize the interactions between glyconanoparticles and lectins. By titrating lectins into the glyconanoparticle solution, the apparent dissociation constant, thermodynamic parameters, and the number of binding sites were derived simultaneously. For the glyconanoparticles-lectin binding pairs investigated, a 3-5 order of magnitude affinity enhancement over the free ligand-lectin interactions was observed which can be attributed to the multivalent ligand presentation on the nanoparticles. The impact of ligand density was also studied, and results showed that the affinity increased with the number of glycans on the nanoparticle.

  • 60.
    Wang, Xin
    et al.
    Portland State University, United States .
    Norberg, Oscar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Deng, Lingquan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. Portland State University, United States .
    Synthesis of Glyconanomaterials via Photo-Initiated Coupling Chemistry2011In: Petite and sweet: glyco-nanotechnology as a bridge to new medicines, American Chemical Society (ACS), 2011, Vol. 1091, p. 49-67Conference paper (Refereed)
    Abstract [en]

    Glyconanomaterials, broadly defined as carbohydrate-presenting structures below 100 nm in size, exhibit remarkable chemical and physical properties with high potential for modern biomedical applications. In this chapter, current synthetic approaches for fabricating glyconanomaterials are summarized, with special emphasis on a novel photocoupling strategy to conjugate carbohydrates onto a wide variety of nanomaterials. Based on the photochemically induced reaction of perfluorophenylazide, different glyconanomaterials were efficiently synthesized, and the resulting structures used in a range of applications. The results demonstrate that this approach to carbohydrate presentation at nanomaterial surfaces leads to efficient and selective binding to cognate proteins, enabling new applications in carbohydrate-lectin recognition, profiling, biosensing, screening, cell imaging, and bacteria detection.

  • 61. Wang, Xin
    et al.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    A photochemically initiated chemistry for coupling underivatized carbohydrates to gold nanoparticles2009In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 19, no 47, p. 8944-8949Article in journal (Refereed)
    Abstract [en]

    The sensitive optoelectronic properties of metal nanoparticles make nanoparticle-based materials a powerful tool to study fundamental biorecognition processes. Here we present a new and versatile method for coupling underivatized carbohydrates to gold nanoparticles (Au NPs) via the photochemically induced reaction of perfluorophenylazide (PFPA). A one-pot procedure was developed where Au NPs were synthesized and functionalized with PFPA by a ligand-exchange reaction. Carbohydrates were subsequently immobilized on the NPs by a fast light activation. The coupling reaction was efficient, resulting in high coupling yield as well as high ligand surface coverage. A colorimetric system based on the carbohydrate-modified Au NPs was used for the sensitive detection of carbohydrate-protein interactions. Binding and cross-reactivity studies were carried out between carbohydrate-functionalized Au NPs and lectins. Results showed that the surface-bound carbohydrates not only retained their binding affinities towards the corresponding lectin, but also exhibited affinity ranking consistent with that of the free ligands in solution.

  • 62. Wang, Xin
    et al.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Dye-doped silica nanoparticles as efficient labels for glycans2011In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, no 14, p. 4261-4263Article in journal (Refereed)
    Abstract [en]

    We report that dye-doped fluorescent silica nanoparticles (FSNPs) are highly efficient labels for glycans. Mono- and oligo-saccharides were conjugated to FSNPs using a general photocoupling chemistry. FSNP-labeled glycans were applied to image and detect bacteria, and to study carbohydrate-lectin interactions on a lectin microarray.

  • 63. Wang, Xin
    et al.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Dynamic light scattering as an efficient tool to study glyconanoparticle-lectin interactions2011In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 136, no 20, p. 4174-4178Article in journal (Refereed)
    Abstract [en]

    Glyconanomaterials, an emerging class of bio-functional nanomaterials, have shown promise in detecting, imaging and targeting proteins, bacteria, and cells. In this article, we report that dynamic light scattering (DLS) can be used as an efficient tool to study glyconanoparticle (GNP)-lectin interactions. Silica and Au nanoparticles (NPs) conjugated with D-mannose (Man) and D-galactose (Gal) were treated with the lectins Concanavalin A (Con A) and Ricinus communis agglutinin (RCA(120)), and the hydrodynamic volumes of the resulting aggregates were measured by DLS. The results showed that the particle size grew with increasing lectin concentration. The limit of detection (LOD) was determined to be 2.9 nM for Con A with Man-conjugated and 6.6 nM for RCA(120) with Gal-conjugated silica NPs (35 nm), respectively. The binding affinity was also determined by DLS and the results showed 3-4 orders of magnitude higher affinity of GNPs than the free ligands with lectins. The assay sensitivity and affinity were particle size dependent and decreased with increasing particle diameter. Because the method relies on the particle size growth, it is therefore general and can be applied to nanomaterials of different compositions.

  • 64. Wang, Xin
    et al.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Glyconanomaterials: Synthesis, Characterization, and Ligand Presentation2010In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 22, no 17, p. 1946-1953Article in journal (Refereed)
    Abstract [en]

    Glyconanomaterials, nanomaterials carrying surface-tethered carbohydrate ligands, have emerged and demonstrated increasing potential in biomedical imaging, therapeutics, and diagnostics. These materials combine the unique properties of nanometer-scale objects with the ability to present multiple copies of carbohydrate ligands, greatly enhancing the weak affinity of individual ligands to their binding partners. Critical to the performance of glyconanomaterials is the proper display of carbohydrate ligands, taking into consideration of the coupling chemistry, the type and length of the spacer linkage, and the ligand density. This article provides an overview of the coupling chemistry for attaching carbohydrate ligands to nanomaterials, and discusses the need for thorough characterization of glyconanomaterials, especially quantitative analyses of the ligand density and binding affinities. Using glyconanoparticles synthesized by a versatile photocoupling chemistry, methods for determining the ligand density by colorimetry and the binding affinity with lectins by a fluorescence competition assay are determined. The results show that the multivalent presentation of carbohydrate ligands significantly enhances the binding affinity by several orders of magnitude in comparison to the free ligands in solution. The effect is sizeable even at low surface ligand density. The type and length of the spacer linkage also affect the binding affinity, with the longer linkage promoting the association of bound ligands with the corresponding lectins.

  • 65. Wang, Xin
    et al.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Quantitative Analysis of Multivalent Ligand Presentation on Gold Glyconanoparticles and the Impact on Lectin Binding2010In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 82, no 21, p. 9082-9089Article in journal (Refereed)
    Abstract [en]

    Glyconanomaterials, nanomaterials carrying multiple carbohydrate ligands, provide an excellent platform for sensitive protein recognition. Using nanomaterials as the scaffold, multivalent interactions between glycan ligands and proteins have been demonstrated. However, the quantitative analysis of the binding affinity of these glyconanomaterials has been lacking. In this Article, we report a new method to measure the binding affinity of glyconanoparticle (GNP)-protein interactions based on a fluorescent competition binding assay, which yielded the apparent dissociation constant (K-d) of GNPs with the interacting protein. Au nanoparticles conjugated with underivatized mono-, oligo-, and polysaccharides were synthesized using our recently developed photocoupling chemistry. The affinities of these GNPs with lectins were measured and were several orders of magnitude higher than the corresponding free ligands with lectins. The effect of ligand display on the binding affinity of GNPs was, furthermore, studied where GNPs of varying linker type, spacer length, ligand density, and nanoparticle size were prepared and K-d values determined. The long spacer linker containing hydrocarbon and ethylene oxide units gave the highest binding affinity as well as assay sensitivity. The binding affinity increased with ligand density in general, showing a drastic increase in affinity at low ligand density. In addition, the affinity enhancement was more pronounced on smaller NPs than the larger ones. These results not only demonstrate that the binding affinity of GNPs is highly influenced by how the ligands are presented on the nanoparticles but also pave the way for tailor-made glyconanomaterials with tunable affinity by way of ligand display.

  • 66.
    Xie, Sheng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fukumoto, Ryo
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. University of Massachusetts, United States.
    Anilide Formation from Thioacids and Perfluoroaryl Azides2015In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 80, no 9, p. 4392-4397Article in journal (Refereed)
    Abstract [en]

    A metal-free method for fast and clean anilide formation from perfluoroaryl azide and thioacid is presented. The reaction proved highly efficient, displaying fast kinetics, high yield, and good chemoselectivity. The transformation was compatible with various solvents and tolerant to a wide variety of functional groups, and it showed high performance in polar protic/aprotic media, including aqueous buffer systems.

  • 67.
    Xie, Sheng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Univ Massachusetts Lowell, Dept Chem, Lowell, MA 01854 USA.
    Lopez, Steven A.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Department of Chemistry, University of Massachusetts Lowell, Lowell, MA, United States .
    Houk, K. N.
    1,3-Dipolar Cycloaddition Reactivities of Perfluorinated Aryl Azides with Enamines and Strained Dipolarophiles2015In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 137, no 8, p. 2958-2966Article in journal (Refereed)
    Abstract [en]

    The reactivities of enamines and predistorted (strained) dipolarophiles toward perfluoroaryl azides (PFAAs) were explored experimentally and computationally. Kinetic analyses indicate that PFAAs undergo (3 + 2) cycloadditions with enamines up to 4 orders of magnitude faster than phenyl azide reacts with these dipolarophiles. DFT calculations were used to identify the origin of this rate acceleration. Orbital interactions between the cycloaddends are larger due to the relatively low-lying LUMO of PFAAs. The triazolines resulting from PFAAenamine cycloadditions rearrange to amidines at room temperature, while (3 + 2) cycloadditions of enamines and phenyl azide yield stable, isolable triazolines. The 1,3-dipolar cycloadditions of norbornene and DIBAC also show increased reactivity toward PFAAs over phenyl azide but are slower than enamineazide cycloadditions.

  • 68.
    Xie, Sheng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Manuguri, Sesha
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Hao, Nanjing
    Zhang, Yang
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhou, Juan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. University of Massachusetts, United States .
    Design and synthesis oftheranostic antibiotic nanodrugs that display size-dependent antibacterial activity and luminescenceManuscript (preprint) (Other academic)
  • 69.
    Xie, Sheng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Manuguri, Sesha
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Proietti, Giampiero
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Romson, Joakim
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fu, Ying
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cellular Biophysics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Inge, A. K.
    Wu, B.
    Zhang, Yang
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Häll, Daniel
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Design and synthesis of theranostic antibiotic nanodrugs that display enhanced antibacterial activity and luminescence2017In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, no 32, p. 8464-8469Article in journal (Refereed)
    Abstract [en]

    We report the modular formulation of ciprofloxacin-based pure theranostic nanodrugs that display enhanced antibacterial activities, as well as aggregation-induced emission (AIE) enhancement that was successfully used to image bacteria. The drug derivatives, consisting of ciprofloxacin, a perfluoroaryl ring, and a phenyl ring linked by an amidine bond, were efficiently synthesized by a straightforward protocol from a perfluoroaryl azide, ciprofloxacin, and an aldehyde in acetone at room temperature. These compounds are propeller-shaped, and upon precipitation into water, readily assembled into stable nanoaggregates that transformed ciprofloxacin derivatives into AIE-active luminogens. The nanoaggregates displayed increased luminescence and were successfully used to image bacteria. In addition, these nanodrugs showed enhanced antibacterial activities, lowering the minimum inhibitory concentration (MIC) by more than one order of magnitude against both sensitive and resistant Escherichia coli. The study represents a strategy in the design and development of pure theranostic nanodrugs for combating drug-resistant bacterial infections.

  • 70.
    Xie, Sheng
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China.
    Manuguri, Sesha
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Ramström, Olof
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. University of Massachusetts Lowell, 1 University Ave., Lowell, MA 01854, United States.
    Yan, Mingdi
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. University of Massachusetts Lowell, 1 University Ave., Lowell, MA 01854, United States.
    Impact of Hydrogen Bonding on the Fluorescence of N-Amidinated Fluoroquinolone2019In: Chemistry - An Asian Journal, ISSN 1861-4728, E-ISSN 1861-471X, Vol. 14, no 6, p. 910-916Article in journal (Refereed)
    Abstract [en]

    The fluorescence properties of AIE-active N-amidinated fluoroquinolones, efficiently obtained by a perfluoroaryl azide-aldehyde-amine reaction, have been studied. The fluorophores were discovered to elicit a highly sensitive fluorescence quenching response towards guest molecules with hydrogen-bond-donating ability. This effect was evaluated in a range of protic/aprotic solvents with different H-bonding capabilities, and also in aqueous media. The influence of acid/base was furthermore addressed. The hydrogen-bonding interactions were studied by IR, NMR, UV/Vis and time-resolved fluorescence decay, revealing their roles in quenching of the fluorescence emission. Due to the pronounced quenching property of water, the N-amidinated fluoroquinolones could be utilized as fluorescent probes for quantifying trace amount of water in organic solvents.

  • 71.
    Xie, Sheng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. University of Massachusetts Lowell, United States.
    N,N-Diethylurea-Catalyzed Amidation between Electron-Deficient Aryl Azides and Phenylacetaldehydes2015In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 17, no 3, p. 636-639Article in journal (Refereed)
    Abstract [en]

    Urea structures, of which N,N-diethylurea (DEU) proved to be the most efficient, were discovered to catalyze amidation reactions between electron-deficient aryl azides and phenylacetaldehydes. Experimental data support 1,3-dipolar cycloaddition between DEU-activated enols and electrophilic phenyl azides, especially perfluoroaryl azides, followed by rearrangement of the triazoline intermediate. The activation of the aldehyde under near-neutral conditions was of special importance in inhibiting dehydration/aromatization of the triazoline intermediate, thus promoting the rearrangement to form aryl amides.

  • 72.
    Xie, Sheng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. University of Massachusetts, United States .
    Photo-activatable switch-on fluorescence through intramolecular C-H insertion of azide derivativesManuscript (preprint) (Other academic)
  • 73.
    Xie, Sheng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhang, Yang
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. University of Massachusetts, United States .
    Base-catalysed synthesis of aryl amides from aryl azides and aldehydesManuscript (preprint) (Other academic)
  • 74.
    Xie, Sheng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhang, Yang
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Base-catalyzed synthesis of aryl amides from aryl azides and aldehydes2016In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 7, no 1, p. 713-718Article in journal (Refereed)
    Abstract [en]

    Aryl amides have been used as important compounds in pharmaceuticals, materials and in molecular catalysis. The methods reported to prepare aryl amides generally require very specific reagents, and the most popular carboxyl-amine coupling reactions demand stoichiometric activators. Herein, we report that aryl azides react with aldehydes under base-catalyzed conditions to yield aryl amides efficiently. Mechanistic investigations support the formation of triazoline intermediates via azide-enolate cycloaddition, which subsequently undergo rearrangement to give amides by either thermal decomposition (20-140 degrees C) or aqueous acid work-up at room temperature. The strategy does not require nucleophilic anilines and is especially efficient for highly electron-deficient aryl amides, including perfluoroaryl amides, which are otherwise challenging to synthesize.

  • 75.
    Xie, Sheng
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Zhou, Juan
    Chen, Xuan
    Univ Massachusetts Lowell, Dept Chem, Lowell, MA 01854 USA..
    Kong, Na
    Fan, Yanmiao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Hammer, Gerry
    Univ Washington, Dept Bioengn, Natl ESCA & Surface Anal Ctr Biomed Problems, Seattle, WA 98195 USA.;Univ Washington, Dept Chem Engn, Natl ESCA & Surface Anal Ctr Biomed Problems, Seattle, WA 98195 USA..
    Castner, David G.
    Univ Washington, Dept Bioengn, Natl ESCA & Surface Anal Ctr Biomed Problems, Seattle, WA 98195 USA.;Univ Washington, Dept Chem Engn, Natl ESCA & Surface Anal Ctr Biomed Problems, Seattle, WA 98195 USA..
    Ramström, Olof
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Yan, Mingdi
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    A versatile catalyst-free perfluoroaryl azide-aldehyde-amine conjugation reaction2019In: MATERIALS CHEMISTRY FRONTIERS, ISSN 2052-1537, Vol. 3, no 2, p. 251-256Article in journal (Refereed)
    Abstract [en]

    In a tri-component reaction, an electrophilically-activated perfluoroaryl azide, an enolizable aldehyde and an amine react readily at room temperature without any catalysts in solvents including aqueous conditions to yield a stable amidine conjugate. The versatility of this reaction is demonstrated in the conjugation of an amino acid without prior protection of the carboxyl group, and in the synthesis of antibiotic-nanoparticle conjugates.

  • 76.
    Yan, Mingdi
    Department of Chemistry, Portland State University.
    Photochemically initiated single polymer immobilization2007In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 13, no 15, p. 4138-4144Article in journal (Refereed)
    Abstract [en]

    This Concept article surveys methods for attaching single polymer molecules on solid substrates. A general approach to single polymer immobilization based on the photochemistry of perfluorophenylazides is elaborated.

  • 77.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. Univ Massachusetts Lowell, Dept Chem, Lowell, MA USA.;KTH, Chem, Stockholm, Sweden..
    Synthesis and photocatalytic activity of covalently conjugated three-dimensional pristine graphene-TiO2 nanocomposite2017In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 253Article in journal (Other academic)
  • 78.
    Yan, Mingdi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Bartlett, Michele A.
    Polymeric structures, particularly microstructures, and methods for making same2001Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Methods of adhering polymeric materials to a substrate, either directly or through linker molecules, are disclosed. Structures, for example, microstructures, including microwells and arrays of microwells, may be readily formed using the methods. In some embodiments, microstructures formed completely from polymeric materials are provided, making it possible to tailor the chemical and physical properties of the microstructures. For example, microwells having a bottom comprising a polar polymeric material and well sides/top comprising a non-polar polymeric material are provided. Biochemical reagents may be easily delivered to such "smart wells" because the intrinsic attraction of the well bottom for the reagents and the intrinsic repulsion between the well sides/top combine to direct the reagents to the wells.

  • 79.
    Yan, Mingdi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Liu, Li-Hong
    Gann, John
    Immobilization of discrete molecules2007Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Embodiments of a method for covalently immobilizing one or more discrete molecules on a substrate and embodiments of substrates having covalently-immobilized discrete molecules are disclosed. Embodiments of the method can include exposing a substrate to a functionalizing reagent to form a functionalized substrate and exposing the functionalized substrate to a solution comprising the molecule to be immobilized. A reaction-energy source then can be used to activate the functionalizing reagent and covalently bond one or more of the molecules to the substrate. All or a substantial portion of the unbonded molecules then can be removed. Controlling the concentration of the functionalizing reagent to which the substrate is exposed allows the density of the bonding sites on the substrate to be reduced so that, after removal of the unbonded molecules, at least one of the bonded molecules remains on the substrate spatially isolated from any other bonded molecules.

  • 80.
    Yan, Mingdi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Moleculary Imprinted Materials: Science and Technology2005Book (Refereed)
  • 81.
    Yan, Mingdi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Preface2005In: Molecularly Imprinted Materials: Science and Technology, New York: Taylor & Francis , 2005Chapter in book (Other academic)
  • 82.
    Yan, Mingdi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Liu, Li-Hong
    Method for functionalizing materials and devices comprising such materials2007Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Devices comprising functionalized materials, and embodiments of a method for making and using such devices, are disclosed. Exemplary devices include ophthalmic devices, nanoparticles, quartz crystal microbalances, microarrays, and nanocomposites. In particular embodiments, device surfaces are modified with monomers and/or polymers, typically carbohydrate monomers and/or polymers. Embodiments of a method for making and using such devices are disclosed. Monomers and/or polymers are covalently bonded to surfaces using functionalized perhalophenylazides. In some embodiments, devices surfaces are functionalized with a perhalophenylazide. One or more monomers and/or polymers subsequently are covalently bonded to the device surface using the perhalophenylazide. In other embodiments, monomers and/or polymers are derivatized with a functionalized perhalophenylazide.; The derivatized monomers and/or polymers then are covalently bonded to the device surface using the perhalophenylazide.

  • 83.
    Yan, Mingdi
    et al.
    Department of Chemistry, Portland State University.
    Ren, J.
    Covalent immobilization of polypropylene thin films2005In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 15, no 4, p. 523-527Article in journal (Refereed)
    Abstract [en]

    This article describes a simple and versatile approach to the covalent attachment of ultrathin polypropylene films on silicon wafers. The immobilization was accomplished by way of the C-H insertion reaction of perfluorophenyl nitrenes generated by thermolysis or photolysis of perfluorophenyl azides. Covalently immobilized thin films of crystalline and amorphous polypropylene and an elastomeric copolymer of polypropylene were successfully fabricated. Patterned polypropylene films were also delineated.

  • 84.
    Yan, Mingdi
    et al.
    Department of Chemistry, Portland State University.
    Ren, J.
    Covalent immobilization of ultrathin polymer films by thermal activation of perfluorophenyl azide2004In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 16, no 9, p. 1627-1632Article in journal (Refereed)
    Abstract [en]

    The attachment of thin films on solid materials is an effective way to tailor the chemical and physical properties of the surface layer. In this article, we report an alternative approach to the covalent immobilization of ultrathin polymer films. The immobilization chemistry is based on the C-H/N-H insertion reaction of perfluorophenyl nitrenes that were generated by the thermal activation of perfluorophenyl azides (PFPAs). In the process, a silicon wafer was treated with PFPA-silane 1 to give a monolayer of azido groups on the surface. A polymer was then spin coated on the functionalized wafer and the sample was heated. Thermolysis produced perfluorophenyl nitrenes which underwent insertion reactions with the neighboring polymer chains. Removal of the excess polymer by solvent extraction resulted in nanometer-thick polymer thin films covalently attached to the wafer surface. Using polystyrene and poly(2-ethyl-2-oxazoline) as examples, covalently immobilized thin films with thicknesses ranging from a few to over a hundred A were obtained. The thickness of the film could be controlled by the type and the molecular weight of the polymer. Patterned polymer films were also fabricated using this method.

  • 85.
    Yan, Mingdi
    et al.
    Portland State Univ, Dept Chem, Portland.
    Ren, J.
    Joshi, R.
    Taylor, M.
    Functionalized perfluophenyl azides for the covalent immobilization of ultrathin polymer films and molecular recognition2004In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 227, p. U510-U510Article in journal (Other academic)
  • 86.
    Yan, Mingdi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Tong, Qi
    Kubo, Takuya
    Wang, Hui
    Functional polymers for the efficient fabrication of carbohydrate microarrays2011In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 241Article in journal (Other academic)
  • 87. Zeng, Zhiyang
    et al.
    Patel, Jiten
    Lee, Shih-Hui
    McCallum, Monica
    Tyagi, Anuradha
    Yan, Mingdi
    Shea, Kenneth J.
    Synthetic Polymer Nanoparticle-Polysaccharide Interactions: A Systematic Study2012In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, no 5, p. 2681-2690Article in journal (Refereed)
    Abstract [en]

    The interaction between synthetic polymer nanoparticles (NPs) and biomacromols. (e.g., proteins, lipids, and polysaccharides) can profoundly influence the NPs fate and function. Polysaccharides (e.g., heparin/heparin sulfate) are a key component of cell surfaces and the extracelluar matrix and play crit. roles in many biol. processes. We report a systematic investigation of the interaction between synthetic polymer nanoparticles and polysaccharides by ITC, SPR, and an anticoagulant assay to provide guidelines to engineer nanoparticles for biomedical applications. The interaction between acrylamide nanoparticles (∼30 nm) and heparin is mainly enthalpy driven with submicromolar affinity. Hydrogen bonding, ionic interactions, and dehydration of polar groups are identified to be key contributions to the affinity. It has been found that high charge d. and crosslinking of the NP can contribute to high affinity. The affinity and binding capacity of heparin can be significantly diminished by an increase in salt concn. while only slightly decreased with an increase of temp. A striking difference in binding thermodn. has been obsd. when the main component of a polymer nanoparticle is changed from acrylamide (enthalpy driven) to N-isopropylacryalmide (entropy driven). This change in thermodn. leads to different responses of these two types of polymer NPs to salt concn. and temp. Select synthetic polymer nanoparticles have also been shown to inhibit protein-heparin interactions and thus offer the potential for therapeutic applications. [on SciFinder(R)]

  • 88.
    Zhang, Yan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Jayawardena, H. Surangi N.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. University of Massachusetts Lowell, MA, United States.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Enzyme classification using complex dynamic hemithioacetal systems2016In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 52, no 28, p. 5053-5056Article in journal (Refereed)
    Abstract [en]

    A complex dynamic hemithioacetal system was generated for the evaluation of lipase reactivities in organic media. In combination with pattern recognition methodology, twelve different lipases were successfully classified into four distinct groups following their reaction selectivities and reactivities. A probe lipase was further categorized using the training matrix with predicted reactivity.

  • 89.
    Zhang, Yan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Jayawardena, Surangi
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Classification of Lipases Using Pattern Recognition through Transformation of Dynamic Hemithioacetal SystemsArticle in journal (Other academic)
    Abstract [en]

    A complex dynamic hemithioacetal system was generated for the evaluation of lipase reactivities. In combination with pattern recognition methodology, twelve different lipases were successfully classified into three distinct groups following their reaction selectivities and reactivities. A probe lipase was further categorized using the training matrix with predicted reactivity.

  • 90.
    Zhang, Yang
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Karalius, Antanas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kinetics and Thermodynamics of Dynamic Nitroaldol Systems in Neutral Aqueous MediaManuscript (preprint) (Other academic)
  • 91.
    Zhang, Yang
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Xie, Sheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Dynamic Covalent Chemistry of Aldehyde Enamines: Bi(III) and Sc(III) catalysis of amine-enamine exchangeManuscript (preprint) (Other academic)
  • 92.
    Zhang, Yang
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Xie, Sheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Dynamic Covalent Chemistry of Aldehyde Enamines: Bi-III- and Sc-III-Catalysis of Amine-Enamine Exchange2017In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, no 49, p. 11908-11912Article in journal (Refereed)
    Abstract [en]

    The dynamic exchange of enamines from secondary amines and enolizable aldehydes has been demonstrated in organic solvents. The enamine exchange with amines was efficiently catalyzed by Bi(OTf)(3) and Sc(OTf)(3) (2mol%) and the equilibria (60mm) could be attained within hours at room temperature. The formed dynamic covalent systems displayed high stabilities in basic environment with <2% by-product formation within one week after complete equilibration. This study expands the scope of dynamic C-N bonds from imine chemistry to enamines, enabling further dynamic methodologies in exploration of this important class of structures in systems chemistry.

  • 93.
    Zhang, Yang
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Xie, Sheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Enzyme- and Ruthenium-Catalyzed Dynamic Kinetic Resolution Involving Cascade Alkoxycarbonylations for Asymmetric Synthesis of 5-Substituted N-AryloxazolidinonesManuscript (preprint) (Other academic)
  • 94.
    Zhang, Yang
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Xie, Sheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Yan, Mingdi
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Ramström, Olof
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Enzyme- and ruthenium-catalyzed dynamic kinetic resolution involving cascade alkoxycarbonylations for asymmetric synthesis of 5-Substituted N-Aryloxazolidinones2019In: Molecular Catalysis, ISSN 2468-8231, Vol. 470, p. 138-144Article in journal (Refereed)
    Abstract [en]

    AAsymmetric synthesis of N-aryloxazolidinones via dynamic kinetic resolution was developed. A ruthenium-based catalyst was used in the racemization of beta-anilino alcohols, while Candida antarctica lipase B (CAL-B) was applied for two selective alkoxycarbonylations operating in cascade. Various N-aryloxazolidinone derivatives were obtained in high yields and good enantiopurities.

  • 95.
    Zhang, Yang
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Zhang, Yan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Xie, Sheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lipase-catalyzed kinetic resolution of 3-phenyloxazolidin-2-one derivatives: Cascade O- and N-alkoxycarbonylations2016In: Catalysis communications, ISSN 1566-7367, E-ISSN 1873-3905, Vol. 82, p. 11-15Article in journal (Refereed)
    Abstract [en]

    A lipase-catalyzed, cascade kinetic resolution protocol has been established for the synthesis of 3-phenyloxazolidin-2-one derivatives with up to excellent enantioselectivities (95% ee). Candida antarctica lipase B showed high catalytic activity and stereoselectivity in sequential O- and N-alkoxycarbonylation processes.

  • 96.
    Zhang, Yang
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhang, Yan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Xie, Sheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lipase-Catalyzed Kinetic Resolution of 3-Phenyloxazolidin-2-one Derivatives: CascadeO‐ and N‐AlkoxycarbonylationsManuscript (preprint) (Other academic)
  • 97.
    Zhou, Juan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Butchosa, Nuria
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Jayawardena, H. Surangi N.
    Zhou, Qi
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Glycan-Functionalized Fluorescent Chitin Nanocrystals for Biorecognition Applications2014In: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 25, no 4, p. 640-643Article in journal (Refereed)
    Abstract [en]

    A new platform based on chitin nanocrystals has been developed for biorecognition applications. TEMPO-oxidized chitin nanocrystals (TCNs) were labeled with a fluorescent imidazoisoquinolinone dye, and simultaneously conjugated with carbohydrate ligands, resulting in dually functionalized TCNs. The biorecognition properties of the nanocrystals were probed with lectins and bacteria, resulting in selective interactions with their corresponding cognate carbohydrate-binding proteins, as visualized by optical, fluorescence, STEM, and TEM imaging. This represents a new approach to multifunctional nanomaterials based on naturally occurring polymers, holding high potential for biomedical applications.

  • 98.
    Zhou, Juan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Butchosa, Núria
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Jayawardena, H. Surangi N.
    University of Massachusetts, United States .
    Park, JaeHyeung
    University of Massachusetts, United States .
    Zhou, Qi
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. University of Massachusetts, United States .
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Synthesis of Multifunctional Cellulose Nanocrystals for Lectin Recognition and Bacterial Imaging2015In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 16, no 4, p. 1426-1432Article in journal (Refereed)
    Abstract [en]

    Multifunctional cellulose nanocrystals have been synthesized and applied as a new type of glyconanomaterial in lectin binding and bacterial imaging. The cellulose nanocrystals were prepared by TEMPO-mediated oxidation and acidic hydrolysis, followed by functionalization with a quinolone fluorophore and carbohydrate ligands. The cellulose nanocrystals were subsequently applied in interaction studies with carbohydrate-binding proteins and in bacterial imaging. The results show that the functional cellulose nanocrystals could selectively recognize the corresponding cognate lectins. In addition, mannosylated nanocrystals were shown to selectively interact with FimH-presenting E. coli, as detected by TEM and confocal fluorescence microscopy. These glyconanomaterials provide a new application of cellulose nanocrystals in biorecognition and imaging.

  • 99.
    Zhou, Juan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Hao, Nanjing
    De Zoyza, Thareendra
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. University of Massachusetts, United States.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lectin-gated, mesoporous, photofunctionalized glyconanoparticles for glutathione-responsive drug delivery2015In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 48, p. 9833-9836Article in journal (Refereed)
    Abstract [en]

    A stimuli-responsive drug delivery system based on fluorescent, lectin-gated, mesoporous glyconanoparticles has been developed and evaluated in normal- and cancer lung epithelial cells. The gating process proved efficient, exhibiting good sealing properties in the absence of the glutathione redox trigger, avoiding premature release in normal cells. In the presence of higher levels of glutathione in cancer cells, the lectin gate was rapidly opened and the anticancer drug released.

  • 100.
    Zhou, Juan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Jayawardana, Kalana
    University of Massachusetts, United States .
    Kong, Na
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ren, Yansong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Hao, Nanjing
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. University of Massachusetts, United States .
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Trehalose-Conjugated Mesoporous Silica Nanoparticles for Efficient Delivery of Isoniazid into MycobacteriaManuscript (preprint) (Other academic)
123 51 - 100 of 101
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