▎ 摘　　要

NOVELTY - Preparing hybrid biofunctional composites comprising reduced graphene oxide (RGO), polyethylenimine (PEI) and an enzyme comprises: (a) providing an aqueous solution of graphene oxide (GO); (b) reducing the GO by adding PEI to the aqueous solution thus obtaining an aqueous RGO-PEI solution; and (c) mixing the aqueous RGO-PEI solution with an enzyme thus obtaining the hybrid biofunctional composite. The RGO and the PEI form covalent bonds and PEI forms a biocompatible matrix electrostatically encapsulating the enzyme inside the matrix. USE - The method is useful for preparing hybrid biofunctional composites which is used: as an enzyme-based biosensing material for a graphene based biosensors; in conjugating toxic heavy metal ions comprising lead(II) ion, mercury(II) ion or cadmium(II) ion; to clean environmental and water technology; in drug delivery where RGO-PEI captures and releases specific drugs; and in electrode composite structures (all claimed). ADVANTAGE - The method is environmentally friendly and one-step green reduction method. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a hybrid biofunctional composite comprising RGO, PEI and an enzyme, where the RGO and PEI form covalent bonds and where PEI forms a biocompatible matrix electrostatically encapsulating the enzyme inside the matrix.