Self-assembled glucose oxidase/graphene/gold ternary nanocomposites for direct electrochemistry and electrocatalysis

摘要

Graphene–gold nanoparticle nanocomposites (GR–AuNPs)were synthesized and used asamatrix for glu-cose oxidase (GOD) immobilization inglucose sensing.Using layer-by-layer (LBL)method,amultilayered GOD sensor was constructed by alternatively immobilizing GR–AuNPsand GOD onelectrodes.The immo-bilized GOD displayed acouple ofstable and well-definedredox peaks with anelectron transfer rate constant of 3.25 s-1 and a formal potential of -0.452 V in0.1 mol L~(-1) pH 7.0 phosphate buffer solution (PBS). The apparent Michaelis–Mentenconstan tfor glucose was 0.038 mmol L~(-1). This method allowed todetect glucose with asensitivity of3.844 lAmmolL~(-1) cm~(-2), alinear range from 0.02 to2.26 mmol L~(-1), and a detection limit of 4.10 lmol L~(-1) (S/N = 3).The results indicated that the proposed graphene–goldnano-particle nanocomposites were good platforms for enzyme immobilization,thus facilitating the direct electron transfer and biosensi ngapplication.