In the present study, a novel bioinorganic catalytic interface, combining the in situ radical polymerization technique with the noncovalent adsorption method, was successfully fabricated, and its assembly mechanism was explored. The in situ radical polymerization technique was applied to construct a polymer shell around the enzyme surface to form the protein nanocapsule. Then, protein nanocapsules assembled on the surface of graphene oxide (GO) through noncovalent interactions to fabricate the dual-immobilized enzyme system. Here, native organophosphorus hydrolase (OPH) and OPH nanocapsule (nOPH10) were immobilized on GO to form the traditional immobilized OPH (OPH@GO) and dual-immobilized OPH (nOPH10@GO), respectively. The introduced polymer shell could protect the enzyme from various denaturation factors and provide abundant functional groups to interact with supports to strengthen the interactions between them. Compared to native OPH and OPH@GO, the resulting nOPH10@GO exhibited enhanced catalytic activity, stability, and reusability. The nOPH10@GO was further used to construct the biosensor, which exhibited better detection performance compared with that of OPH@GO. These features indicated that the introduced enzyme immobilization system could enhance the enzymatic performance and broaden its application prospect.
Keywords: bioinorganic catalytic interfaces; biosensing; enzyme immobilization; graphene oxide; protein nanocapsule; radical polymerization.