| 1. |
- Al-Bataineh, Sameer A., et al.
(författare)
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Covalent Immobilization of Antibacterial Furanones via Photochemical Activation of Perfluorophenylazide
- 2009
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 25:13, s. 7432-7437
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Tidskriftsartikel (refereegranskat)abstract
- N-(3-Trimethoxysilylpropyl)-4-azido-2,3,5,6-tetrafluorobenzamide (PFPA-silane) was used as a photoactive crosslinker to immobilize antibacterial furanone molecules on silicon oxide surfaces. This immobilization strategy is useful, especially for substrates and molecules that lack reactive functional groups. To this end, cleaned wafers were initially incubated in solutions of different concentrations of PFPA-silane to form a monolayer presenting azido groups on the surface. The functionalized surfaces were then treated with a furanone solution followed by illumination with UV light and extensive rinsing with ethanol to remove noncovalently adhered molecules, In the presented study, we demonstrate the ability to control the surface density of the immobilized furanone molecules by adjusting the concentration of PFPA-silane solution used for surface functionalization using complementary surface analytical techniques. The fluorine in PFPA-silane and the bromine in furanone molecules were convenient markers for the XPS study. The ellipsometric layer thickness of the immobilized furanone molecules on the surface decreased with decreasing PFPA-silane concentration, which correlated with a decline of water contact angle as a sign of film collapse. The intensity of characteristic azide vibration in the MTR IR spectra was monitored as a function of PFPA-silane concentration, and the peak disappeared completely after furanone application followed by UV irradiation. As a complementary technique to XPS, TOF-SIMS provided valuable information on the chemical and molecular structure of the modified surfaces and spatial distribution of the immobilized furanone molecules. Finally, this report presents a convenient, reproducible, and robust strategy to design antibacterial coating based on furanone compounds for applications in human health care.
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| 2. |
- Chada, Sailaja, et al.
(författare)
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Self-assembled nanostructures from homopolymer induced by UV and solvent exposure
- 2008
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 4:11, s. 2164-2167
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Tidskriftsartikel (refereegranskat)abstract
- A simple method for creating self-assembled nanostructures using a single polymer system is reported. When spin-coated polystyrene thin films were irradiated with UV light and treated with toluene, unique nanostructures were observed, evolving from star-shaped networks to arrays of concentric circles. The nanostructure formation is a result of differential responses of crosslinked and oxidized products to the solvent by a combined effect of phase separation and solvent swelling. The nanostructures were observed for polymers of different molecular weights, films of different thicknesses, and on various substrates.
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| 3. |
- Chen, Y. C., et al.
(författare)
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Fluorescence anisotropy studies of molecularly imprinted polymers
- 2006
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Ingår i: Luminescence (Chichester, England Print). - : Wiley. - 1522-7235 .- 1522-7243. ; 21:1, s. 7-14
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Tidskriftsartikel (refereegranskat)abstract
- A molecularly imprinted polymer (MIP) is a biomimetic material that can be used as a biochemical sensing element. We studied the steady-state and time-resolved fluorescence and fluorescence anisotropy of anthracene-imprinted polyurethane. We compared MIPs with imprinted analytes present, MIPs with the imprinted analytes extracted, MIPs with rebound analytes, non-imprinted control polymers (non-MIPs) and non-MIPs bound with analytes to understand MIP’s binding behaviour. MIPs and non-MIPs had similar steady-state fluorescence anisotropy in the range 0.11-0.24. Anthracene rebound in MIPs and non-MIPs had a fluorescence lifetime of tau = 0.64 ns and a rotational correlation time of 0, = 1.2-1.5 ns, both of which were shorter than that of MIPs with imprinted analytes present (tau = 2.03 ns and phi(F) = 2.7 ns). The steady-state anisotropy of polymer solutions increased exponentially with polymerization time and might be used to characterize the polymerization extent in situ.
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| 4. |
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| 5. |
- Harnish, B., et al.
(författare)
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UV-cross-linked poly(vinylpyridine) thin films as reversibly responsive surfaces
- 2005
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 17:16, s. 4092-4096
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Tidskriftsartikel (refereegranskat)abstract
- We report that UV-cross-linked poly(4-vinylpyridine) (P4VP) films acted as reversibly responsive coatings that controlled surface wettability and swelling toward external stimuli: solvent and pH. The polymer films were prepared simply by spin-coating a solution of P4VP followed by UV irradiation. These cross-linked films, when treated with chloroform, showed similar to 31% increase in film thickness whereas films extracted with methylene chloride or n-butanol exhibited a slight decrease. The increase in film thickness was due to the protonation of pyridyl groups by hydrogen chloride resulting from the photodegeneration of chloroform. The film expanded to minimize repulsion around the charged centers. This hypothesis was further confirmed by exposing the cross-linked film to hydrogen chloride vapor. The film expanded similar to 37% whereas no thickness increase was observed for films exposed to ammonia or methanol vapors. The extent of swelling was monitored in situ using a quartz crystal microbalance sensor. Large oscillation frequency shifts were detected when the UV-cross-linked P4VP film was exposed to acidic buffer solutions. The changes were rapid, and the effect was reversible.
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| 6. |
- Knudsen, Daniel, et al.
(författare)
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Creating Microstructures on Silicon Wafers Using UV-Crosslinked Polystyrene Thin Films
- 2009
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Ingår i: Polymer Engineering and Science. - : Wiley. - 0032-3888 .- 1548-2634. ; 49, s. 945-948
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Tidskriftsartikel (refereegranskat)abstract
- We report that UV-crosslinked polystyrene (PS) thin films can be used as an inexpensive wet chemical etch resist to create microstructures on silicon wafers. When spin-coated PS films were irradiated, the polymer undergoes UV-induced crosslinking. Patterned PS films were successfully used as the protective layer withstanding chemical etching with the buffered HF solution. Removal of the polymer films by sonicating in water generated microstructures in silicon wafers. This simple and environmentally friendly procedure employs inexpensive commodity polymer and eliminates the use of organic solvents and harsh conditions in the subsequent development process. POLYM. ENG. SCI., 49:945-948, 2009. (C) 2009 Society of Plastics Engineers
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| 7. |
- Liu, Li, et al.
(författare)
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A general approach to the covalent immobilization of single polymers
- 2006
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 45:37, s. 6207-6210
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Tidskriftsartikel (refereegranskat)abstract
- Stuck fast: The covalent immobilization of polymeric single molecules is achieved by the photochemically induced C-H/N-H insertion reaction of perfluorophenylazides (see picture). When the concentration of the surface azido groups is decreased, isolated polymeric single molecules are observed. This technique is especially suited for materials that do not possess functional groups and are difficult to be immobilized by other means. (Chemical Equation Presented).
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| 8. |
- Liu, Li-Hong, et al.
(författare)
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Photoinitiated Coupling of Unmodified Monosaccharides to Iron Oxide Nanoparticles for Sensing Proteins and Bacteria
- 2009
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Ingår i: Bioconjugate chemistry. - : American Chemical Society (ACS). - 1043-1802 .- 1520-4812. ; 20:7, s. 1349-1355
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Tidskriftsartikel (refereegranskat)abstract
- We report a versatile approach for the immobilization of unmodified monosaccharides onto iron oxide nanoparticles. Covalent coupling of the carbohydrate onto iron oxide nanoparticle surfaces was accomplished by the CH insertion reaction of photochemically activated phosphate-functionalized perfluorophenylazides (PFPAs), and the resulting glyconanoparticles were characterized by IR, TGA, and TEM. The surface-bound D-mannose showed the recognition ability toward Concanavalin A and Escherichia coli strain ORN178 that possesses mannose-specific receptor sites. Owing to the simplicity and versatility of the technique, together with the magnetic property of iron oxide nanoparticles, the methodology developed in this study serves as a general approach for the preparation of magnetic glyconanoparticles to be used in clinical diagnosis, sensing, and decontamination.
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| 9. |
- Liu, Li-Hong, et al.
(författare)
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Simple Method for the Covalent Immobilization of Graphene
- 2009
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 9:9, s. 3375-3378
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Tidskriftsartikel (refereegranskat)abstract
- We present a simple and efficient method to immobilize graphene on silicon wafers using perfluorophenylazide (PFPA) as the coupling agent. Graphene sheets were covalently attached to PFPA-functionalized wafer surface by a simple heat treatment under ambient conditions. The formation of single and multiple layers of graphene were confirmed by Raman spectroscopy and optical and atomic force microscopy. Evidence of covalent bond formation between graphene and PFPA decorated silicon wafer was given by X-ray photoelectron spectroscopy and sonication treatment.
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| 10. |
- Liu, Li, et al.
(författare)
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Surface and interface control on photochemically initiated immobilization
- 2006
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 128:43, s. 14067-14072
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Tidskriftsartikel (refereegranskat)abstract
- Surface and interface properties are important in controlling the yield and efficiency of the photochemically initiated immobilization. Using a silane-functionalized perfluorophenyl azide (PFPA-silane) as the photoactive cross-linker, the immobilization of polymers was studied by adjusting the density of the surface azido groups. Dilution of the photolinker resulted in a gradual decrease in the density of surface azido groups as well as the thickness of the immobilized film. When a nonphotoactive silane was added to PFPA-silane, the film thickness decreased more rapidly, suggesting that the additive competed with PFPA-silane and effectively reduced the density of the surface azido groups. The effect of surface topography was studied by adding a nonphotoactive silane with either a shorter (n-propyltrimethoxysilane (PTMS)) or a longer spacer (n-octadecyltrimethoxysilane (ODTMS)). In most cases the long chain ODTMS shielded the surface azido groups, resulting in a more rapid decrease in film thickness as compared to PTMS treated under the same conditions. As the density of the surface azido groups decreased, the immobilized polymer changed from smooth films to patched structures and, eventually, single polymer molecules.
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| 11. |
- Liu, Wei, et al.
(författare)
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Surface plasmon resonance imaging of limited glycoprotein samples
- 2008
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Ingår i: The Analyst. - : Royal Society of Chemistry (RSC). - 0003-2654 .- 1364-5528. ; 133:9, s. 1268-1273
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Tidskriftsartikel (refereegranskat)abstract
- A surface plasmon resonance imaging method has been developed for high throughput recognition and determination of low level glycoproteins with limited sample volume at least down to 50 nL. Chicken ovalbumin and immunoglobulin G were chosen as model compounds while bovine serum albumin and lysozyme were used as control. Each protein, at a concentration of 0.0080-1.0 mg mL(-1), was printed on one gold sensing film, and the films were simultaneously reacted with a probe solution and viewed using a laboratory-built surface plasmon resonance imaging system. The imaging signals were dependent on the concentration and the type of analyte, with a limit of detection down to at least 0.5 ng. The glycoproteins dotted at either 1.0 mg mL(-1) or 0.010 mg mL(-1) were easily differentiated from the non-glycoproteins by reaction with 200 nM concanavalin A (con A), giving a limit of recognition down also to 0.5 ng glycoprotein. This imaging method was hence considered a new tool for analyzing glycoproteins.
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| 12. |
- Norberg, Oscar, et al.
(författare)
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Photo-Click Immobilization of Carbohydrates on Polymeric Surfaces - A Quick Method to Functionalize Surfaces for Biomolecular Recognition Studies
- 2009
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Ingår i: Bioconjugate chemistry. - : American Chemical Society (ACS). - 1043-1802 .- 1520-4812. ; 20:12, s. 2364-2370
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Tidskriftsartikel (refereegranskat)abstract
- Methods to rapidly functionalize specific polymeric surfaces with alkynes, which can subsequently be linked to azide-containing carbohydrates, are presented. The methods comprise two main concepts: azide photoligation and Cu-catalyzed azide-alkyne cycloaddition. 2-Azidoethyl-functionalized CL-D-mannopyranoside was synthesized and covalently attached to alkyne-functionalized polymeric surfaces using the techniques. The protein recognition properties of the carbollydrate-presenting surfaces were evaluated using quartz crystal microbalance biosensor instrumentation.
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| 13. |
- Pei, Yuxin, et al.
(författare)
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Photoderivatized polymer thin films at quartz crystal microbalance surfaces : Sensors for carbohydrate-protein interactions
- 2007
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 79:18, s. 6897-6902
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Tidskriftsartikel (refereegranskat)abstract
- Photoderivatized polymer-coated gold surfaces have been developed following a perfluorophenylazide-based double ligation strategy. Gold-plated quartz crystal microbalance (QCM) crystals were initially covalently functionalized with a monolayer of poly(ethylene glycol) (PEG), using photo-or thermolytic nitrene formation and insertion. The polymer surfaces were subsequently used as substrates for photoinsertion of carbohydrate-derivatized photoprobes, yielding different recognition motifs for selective protein binding. The resulting robust and biocompatible sensor surfaces were applied to a flow-through QCM instrument for monitoring lectin-carbohydrate interactions in real time. The results clearly show the predicted lectin selectivity, demonstrating the applicability of the approach.
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| 14. |
- Pei, Zhichao, et al.
(författare)
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Photogenerated Carbohydrate Microarrays
- 2007
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Ingår i: ChemBioChem. - : Wiley-VCH Verlagsgesellschaft. - 1439-4227 .- 1439-7633. ; 8:2, s. 166-168
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Tidskriftsartikel (refereegranskat)abstract
- Chemical Equation Presented) Sugars in a row. A new strategy for carbohydrate microarrays based on photochemical ligation of perfluorophenylazide-derivatized carbohydrates to PEO surfaces is presented. It constitutes a controllable and robust method of array fabrication, on the carbohydrate chemistry and on the surface-chemistry levels, and the resulting carbohydrate arrays can be efficiently used to reveal the recognition patterns of carbohydrate-binding proteins.
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| 15. |
- Ramström, Olof, et al.
(författare)
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Molecular imprinting - An introduction
- 2005
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Ingår i: Molecularly Imprinted Materials. - New York : Taylor & Francis. - 9780824753535 ; , s. 1-12
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Bokkapitel (refereegranskat)
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| 16. |
- Schmid, Daniel, et al.
(författare)
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Melt elongation of polymer nanocomposites : A method for the controlled production of dichroic films
- 2008
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Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 293:6, s. 471-478
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Tidskriftsartikel (refereegranskat)abstract
- A processing method based on stretching of molten polymer nanocomposites was applied to prepare dichroic films. First, dodecanethiol-capped gold particles were embedded in low density polyethylene. The resulting isotropic films were stretched in the melt under uniaxial loading using an elongational rheometer. The melt elongation technique resulted in reproducible characteristics of the optical properties and can be directly transferred to an industrial scale. The organic coating of the metal particles plays an important role in the generation of the dichroism. A reactive surface (adsorbed perfluorophenyl azide) led to strongly agglomerated particles which obviously did not lead to dichroic films.
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| 17. |
- Wang, Xin, et al.
(författare)
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A photochemically initiated chemistry for coupling underivatized carbohydrates to gold nanoparticles
- 2009
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 19:47, s. 8944-8949
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 18. |
- Wang, Xin, et al.
(författare)
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Engineering Nanomaterial Surfaces for Biomedical Applications
- 2009
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Ingår i: Experimental biology and medicine. - : SAGE Publications. - 1535-3702 .- 1535-3699. ; 234:10, s. 1128-1139
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Tidskriftsartikel (refereegranskat)abstract
- 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
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| 19. |
- Yan, Mingdi, et al.
(författare)
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Covalent immobilization of polypropylene thin films
- 2005
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 15:4, s. 523-527
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 20. |
- Yan, Mingdi, et al.
(författare)
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Immobilization of discrete molecules
- 2007
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Patent (populärvet., debatt m.m.)abstract
- 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.
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| 21. |
- Yan, Mingdi, et al.
(författare)
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Method for functionalizing materials and devices comprising such materials
- 2007
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Patent (populärvet., debatt m.m.)abstract
- 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.
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| 22. |
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| 23. |
- Yan, Mingdi
(författare)
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Photochemically initiated single polymer immobilization
- 2007
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 13:15, s. 4138-4144
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 24. |
- Yan, Mingdi, et al.
(författare)
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Preface
- 2005
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Ingår i: Molecularly Imprinted Materials. - New York : Taylor & Francis. - 9780824753535
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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