Coatings for selective cell binding and releasing in cell isolation applications
Toh, Nicole Jia Yi
Date of Issue2016
School of Chemical and Biomedical Engineering
Cell enrichment via a target-specific cell capture and release mechanism is a vital procedure in diagnostics and graft engineering, and one approach to achieve this is with cell-specific antibodies. Antibodies can be immobilized onto a sorting device surface via avidin-biotin interaction, which requires surface functionalization with carboxyl groups first to react with amine-ended biotin. This study aims to optimize the initiating carboxyl functionalization step on hydrophobic polymers. Cyclic Olefin Copolymer (COC) and Poly-methyl-methacrylate (PMMA) were studied due to their commercial availability and biocompatibility. The polymer slides were treated with oxygen (O2) and argon (Ar2) plasmas to determine the effect of treatment duration and gas composition on the generation of radicals, which were quantified by a 2,2-diphenyl-1-pricylhydrazyl (DPPH) assay. Low pressure plasma activation was optimal with a 60 % Ar2 and 40% O2 gas ratio, and treatment for 180s for PMMA, and 120s for COC. The activated slides were coated with acrylic acid (AAc) for UV grafting, and the degree of carboxyl grafting was characterized by a Toluidine Blue-O (TBO) assay. Optimal grafting occurred with 10 min of UV irradiation for both polymers, and AAc concentrations of 60% for COC or 30% for PMMA. Changes in surface wettability were characterized by water contact angle (WCA) measurement to determine the degree of grafting. Changes in morphology after AAc grafting was observed by tapping-mode Atomic Force Microscopy (AFM). It was concluded that the proposed methodology can successfully conjugate carboxylic groups to both polymer surfaces with optimized process parameters.
Final Year Project (FYP)
Nanyang Technological University