Preparation of molecularly imprinted polymers on hemin-graphene surface for recognition of high molecular weight...

Surface molecular imprinting for proteins, especially for the high molecular weight protein, are facing a great challenge today. We report a novel design to prepare molecular imprinting polymers (MIPs) on the surface of hemin-graphene nanosheets (H-GNs) for the recognition of thyroglobulin (Tg, 660 KD). H-GNs with an intrinsic peroxidase-like activity could effectively immobilize the protein template on its surface to improve the number of imprinted sites per unit surface area and then directly initiate free-radical polymerization to synthesize MIPs. The results indicated MIPs film could be prepared on the surface of H-GNs/filter paper, implying the advantages of surface imprinting, and exhibiting high adsorption capacity (400 mg g^-1). The MIP composites clearly distinguished the proteins on the basis of the synergistic effect of shape complementarity and multiple interactions, not even anti-Tg antibodies and sample matrix. The gray intensity of the colorimetric paper-based sensor proved to be proportional to the concentration of Tg in the range of 5-100 ng mL^-1 with a detection limit of 1 ng mL^-1 (15 fM). The design and direct synthesis of MIPs on the H-GNs/filter paper provide a new perspective for the surface imprinting materials with potential in the recognition and detection of proteins.