Unconventional Layer-by-Layer Assembly of Graphene Multilayer Films for Enzyme-Based Glucose and Maltose Biosensing

We have developed an unconventional method for the layer-by-layer (LbL) assembly of graphene multilayer films. Unconventional LbL assembly was achieved by the following two-step process. Graphene sheets were modified by pyrene-grafted poly(acrylic acid) (PAA) in aqueous solution, and then the modified graphene sheets were used for layer-by-layer alternating deposition with poly(ethyleneimine) (PEI). The graphene-multilayer-film-modified electrode shows enhanced electron transfer for the redox reactions of Fe(CN)63− and excellent electrocatalytic activity of H2O2. On the basis of this property, a bienzyme biosensing system for the detection of maltose was fabricated by successive LbL assembly of graphene, glucose oxidase (GOx), and glucoamylase (GA). LbL assembly of graphene combines the excellent electrochemical properties of graphene and the versatility of LbL assembly, showing great promise in highly efficient sensors and advanced biosensing systems.