Papers by Author: Xiao Nong Chen

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Authors: Xiao Nong Chen, Robert Pelton
Abstract: Polystyrene (PS), polyethylene (PE), polypropylene (PP), glass and stainless steel were exposed to aqueous solutions of a series amphiphilic polymers at room temperature, including N-isopropylacrylamide (NIPAM)-based polymers, polyvinylpyrrolidone (PVP), polypropylene oxide (PPO)-polyethylene oxide (PEO) block copolymers and PEO. Dynamic contact angle measurements of the material surfaces before and after the treatment indicate that only NIPAM-based polymers can adsorb on both hydrophobic and hydrophilic surfaces. The surface morphologies of the materials before and after polymer adsorption were investigated by profilometry. Protein adsorption on the surfaces pre-adsorbed NIPAM-based polymers was investigated by dual polarisation interferometry (DPI) and profilometry using lysozyme as the model protein. The results obtained indicate that NIPAM-based polymers can significantly improve the biofouling resistance of synthetic surfaces.
Authors: Xiao Nong Chen, Zai Qian Qi, Ya Qin Huang, Robert Pelton, Raja Ghosh
Abstract: N-isopropylacrylamide (NIPAM)-ethylene oxide (EO) copolymer was grafted on filter paper surface to obtain paper-based adsorptive membrane. Protein adsorption on and release from the membrane was evaluated under various conditions using humanized monoclonal antibody as model protein. The results obtained indicated that amphiphilic copolymer modified filter paper could be used as a novel chromatographic membrane for protein separation/purification. Comb-block copolymers of NIPAM with N-vinylpyrrolidone (VP) were prepared through RAFT polymerization and macromonomer techniques. Surface modification of substrates, such as plastics and glass, was carried out by treatment of the substrates in aqueous solution of the amphiphilic comb-block copolymer (adsorptive coating, pre-adsorption). It was found that the adsorbed copolymer layer was stable in aqueous environment even when shear stress was applied. Protein adhesion on the material surfaces before and after the modification was investigated using lysozyme as model protein. The results obtained showed that the adsorptive coating layer on the material surfaces significantly reduced non-specific protein adhesion.
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