| 1. |
- Chaudhary, Shilpi, et al.
(författare)
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Controlled short-linkage assembly of functional nano-objects
- 2014
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Ingår i: Applied Surface Science. - : Elsevier BV. - 1873-5584 .- 0169-4332. ; 300, s. 22-28
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we report a method that allows the deterministic, photo-controlled covalent assembly of nanoparticles directly on surface. As a model system, we study the conjugation of molecularly imprinted polymer (MIP) nanoparticles on a glass surface and confirm that the immobilized nanoparticles maintain their molecular recognition functionality. The glass slide was first modified with perfluorophenylazide and then used to bind MIP nanoparticles under UV irradiation. After each step the surface was analyzed by water contact angle measurement, fluorescence microscopy, scanning electron microscopy, and/or synchrotron-based X-ray photoelectron spectroscopy. The MIP nanoparticles immobilized on the glass surface remained stable and maintained specific binding for the template molecule, propranolol. The method developed in this work allows MIP nanoparticles to be directly coupled to a flat surface, offering a straightforward means to construct robust chemical sensors. Using the reported photo conjugation method, it is possible to generate patterned assembly of nanoparticles using a photomask. Since perfluorophenylazide-based photochemistry works with all kinds of organic material, the method developed in this work is expected to enable immobilization of not only MIPs but also other kinds of organic and inorganic-organic core-shell particles for various applications involving photon or electron transfer. (C) 2014 The Authors. Published by Elsevier B.V. All rights reserved.
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| 2. |
- Xu, Changgang, et al.
(författare)
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Photoconjugation of Molecularly Imprinted Polymer with Magnetic Nanoparticles.
- 2013
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 5:11, s. 5208-5213
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Tidskriftsartikel (refereegranskat)abstract
- Because of their synthetic accessibility, molecularly imprinted polymer (MIP) nanoparticles are ideal building blocks for preparing multifunctional composites. In this work, we developed a general photocoupling chemistry to enable simple conjugation of MIP nanoparticles with inorganic magnetic nanoparticles. We first synthesized MIP nanoparticles using propranolol as a model template and perfluorophenyl azide-modified silica-coated magnetic nanoparticles. Using a simple photoactivation followed by facile purification with a magnet, we obtained magnetic composite particles that showed selective uptake of propranolol. We characterized the nanoparticles and composite materials using FT-IR, TEM, fluorescence spectroscopy, and radioligand binding analysis. Through the high molecular selectivity of the magnetic composite, we demonstrated the nondestructive feature and the high efficiency of the photocoupling chemistry. The versatile photoconjugation method developed in this work should also be very useful for combining organic MIPs with other inorganic nanoparticles to enable new chemical sensors and high efficiency photocatalysts.
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| 3. |
- Xu, Zhifeng, et al.
(författare)
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Boronic Acid Terminated Thermo-Responsive and Fluorogenic Polymer: Controlling Polymer Architecture for Chemical Sensing and Affinity Separation
- 2012
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 45:16, s. 6464-6470
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Tidskriftsartikel (refereegranskat)abstract
- Thermo-responsive poly(N-isopropylacrylamide) (polyNIPAm) containing terminal boronic acid was synthesized using atom transfer radical polymerization (ATRP) in combination with Cu(I)-catalyzed alkyne-azide 1,3-dipolar cycloaddition (CuAAC) reaction. Alkyne-terminated polyNIPAm was first synthesized by ATRP using an alkyne-containing initiator. A fluorogenic boronic acid, 3-(2-azido-acetylamino)phenylboronic acid (APBA) was then linked to the polyNIPArn through CuAAC. The synthesized polymers were characterized by H-1 NMR, FT-IR, UV-vis, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, and turbidity measurements. The intensity of fluorescence emission of the boronic acid-terminated polyNIPAm (BA-polyNIPAm) was found to increase when increasing amount of a cis-diol compound (i.e., fructose) was added. At physiological pH value, the BA-polyNIPAm effectively bound fructose and could be easily separated from aqueous solution by raising the temperature above its lower critical solution temperature (LCST).
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| 4. |
- Xu, Zhifeng, et al.
(författare)
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Fluorescent Boronic Acid Polymer Grafted on Silica Particles for Affinity Separation of Saccharides.
- 2014
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 6:3, s. 1406-1414
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Tidskriftsartikel (refereegranskat)abstract
- Boronic acid affinity gels are important for effective separation of biological active cis-diols, and are finding applications both in biotech industry and in biomedical research areas. To increase the efficacy of boronate affinity separation, it is interesting to introduce repeating boronic acid units in flexible polymer chains attached on solid materials. In this work, we synthesize polymer brushes containing boronic acid repeating units on silica gels using surface-initiated atom transfer radical polymerization (ATRP). A fluorescent boronic acid monomer is first prepared from an azide-tagged fluorogenic boronic acid and an alkyne-containing acrylate by Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction (the CuAAC click chemistry). The boronic acid monomer is then grafted to the surface of silica gel modified with an ATRP initiator. The obtained composite material contains boronic acid polymer brushes on surface and shows favorable saccharide binding capability under physiological pH conditions, and displays interesting fluorescence intensity change upon binding fructose and glucose. In addition to saccharide binding, the flexible polymer brushes on silica also enable fast separation of a model glycoprotein based on selective boronate affinity interaction. The synthetic approach and the composite functional material developed in this work should open new opportunities for high efficiency detection, separation, and analysis of not only simple saccharides, but also glycopeptides and large glycoproteins.
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