Surface Modification And Performance Of Polystyrene Microtitre Plates Via ⁶⁰Co Radiation

Polystyrene (PS) micro-plate is the most commonly used solid phase carrier for ELISA (Enzyme-linked immunosorbent assay, ELISA), however, the hydrophobic structural is easily to make the adsorbed protein deformed and inactivated. PS micro-plates mainly combined the protein/peptide by physical adsorption, during the operation, it is easily to make the protein/polypeptide off, resulting in unstable measurement results. Therefore, the surface modification of PS micro-plates is necessary.In this paper, six different vinyl monomers (acrylic acid, meth-acrylic acid, fumaric acid,4-vinyl pyridine, methyl-β-hydroxy ethyl methacrylate, poly (ethylene glycol) meth-acrylate) was grafted to the surface of polystyrene micro-plates by 60Co radiation-induced polymerization method, the details are as follows:(1) Configured the different concentrations solution of six kinds vinyl monomers, graft polymerization respectively occurred at the radiation dose of 4kGy,6kGy,8kGy, 10kGy,12kGy.(2) Performed ATR-FTIR and XPS analysis, comparing the functional structure and the surface elements composition of original and grafted PS plates, to make sure the grafting reaction occurs. The results showed that,60Co radiation-induced radical polymerization method can made the six kinds of vinyl monomers grafted to the surface PS micro-plates successfully.(3) XRD and AFM analysis was performed to compare the crystal morphology and surface morphology of original and grafted PS plates. The results showed that the radiation grafting made the surface morphology of PS changed greatly, disrupted the crystalline form of PS and making it more disordered.(4) Studied the relation between absorbance and static water contact angle with irradiation dose and monomer concentration, and determined the optimum reaction conditions. The results showed that the optimal conditions of PS-g-PAA graft system was: irradiation dose of lOkGy, AA monomer concentration of 20% by volume; optimum conditions of PS-g-PMAA graft system was:irradiation dose of 4kGy, MAA monomer concentration of 2% by volume; optimum conditions of PS-g-fumaric acid graft system was: irradiation dose of 8kGy, fumaric acid monomer concentration of 8%; optimum conditions of the PS-g-4VP graft system was:irradiation dose of 8kGy,4VP monomer concentration of 3% by volume; optimum conditions of PS-g-HEMA grafted system was:irradiation dose of 8kGy, HEMA monomer concentration of 3% by volume; optimum conditions PS-g-PEGMA graft system was:irradiation dose of 8kGy, PEGMA monomer concentration of 3% by volume.(5) Researched the BSA adsorption of the grafted PS under optimal reaction conditions. The results showed that the BSA adsorption of PS-g-PAA graft system was 21.12 μg/cm2; the BSA adsorption of PS-g-PMAA graft system was 31.10 μg/cm2; the BSA adsorption of PS-g-fumaric acid graft system was 9.33 μg/cm2; the BSA adsorption of PS-g-4VP graft system was 42.00 μg/cm2; the BSA adsorption of PS-g-PEGMA graft system has declined.