Reduced graphene oxide/PAMAM–silver nanoparticles nanocomposite modified electrode for direct electrochemistry of glucose oxidase and glucose sensing

Reduced graphene oxide/PAMAM–silver nanoparticles nanocomposite (RGO–PAMAM–Ag) was synthesized by self-assembly of carboxyl-terminated PAMAM dendrimer (PAMAM-G3.5) on graphene oxide (GO) as growing template, and in-situ reduction of both AgNO3 and GO under microwave irradiation. The RGO–PAMAM–Ag nanocomposite was used as a novel immobilization matrix for glucose oxidase (GOD) and exhibited excellent direct electron transfer properties for GOD with the rate constant (Ks) of 8.59 s−1. The fabricated glucose biosensor based on GOD electrode modified with RGO–PAMAM–Ag nanocomposite displayed satisfactory analytical performance including high sensitivity (75.72 μA mM−1 cm−2), low detection limit (4.5 μM), an acceptable linear range from 0.032 mM to 1.89 mM, and also preventing the interference of some interfering species usually coexisting with glucose in human blood at the work potential of −0.25 V. These results indicated that RGO–PAMAM–Ag nanocomposite is a promising candidate material for high-performance glucose biosensors.

► Synthesis method of self-assembly and in-situ reduction was used.
► Homogeneous Ag nanoparticles were synthesized on reduced graphene oxide.
► GO and AgNO3 were reduced by PAMAM dendrimers under microwave irradiation.
► The direct electron transfer rate constant for glucose oxidase could reach 8.59 s−1.
► The fabricated glucose biosensor displayed satisfactory analytical performance.