Improvement of recognition specificity of surface protein-imprinted magnetic microspheres by reducing nonspecific adsorption of competitors using 2-methacryloyloxyethyl phosphorylcholine

A novel bovine serum albumin (BSA) surface-imprinted magnetic microsphere was fabricated by copolymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC), functional monomer acrylamide and cross-linking agent N,N′-methylenebisacrylamide on the surface of Fe₃O₄@SiO₂ microsphere. Here, MPC was creatively and strategically introduced to the protein-imprinted polymer as an assistant monomer to reduce nonspecific adsorption of competitive protein. 10 mol% of MPC was determined as the optimal content according to the imprinting factor. The structure and component of the obtained imprinted microsphere were studied by different characterization methods. The rebinding specificity experiments showed that the recognition specificity of the BSA-imprinted microsphere was greatly improved by introducing MPC. The corresponding adsorption capacity and imprinting factor were 21.79 mg/g and 8.32, respectively. More significantly, the selectivity coefficients of BSA to human serum albumin, ovalbumin, lysozyme, Cytochrome C and Ribonuclease A could reach up to 1.63, 5.23, 9.14, 7.43 and 7.23, respectively, benefited by the protein restricted access function of MPC polymer. Furthermore, this strategy had an excellent versatility and was also suitable for another template, lysozyme. The proposed strategy herein provided an effective means for improving recognition specificity of molecularly imprinted polymers and was expected to use in the improvement of detection sensitivity of molecularly imprinted biosensors.