Preparation of Gold Nanoparticle/Graphene Composites with Controlled Weight Contents and Their Application in Biosensors

Positively charged gold nanoparticles (GNPs) with diameters of 2−6 nm were self-assembled onto the surfaces of 1-pyrene butyric acid functionalized graphene (PFG) sheets simply by mixing their aqueous dispersions. The amount of GNPs assembled on PFG sheets can be easily modulated by controlling the feeding weight ratio of both components. Furthermore, it was found that PFG sheets had a high loading capability of GNPs, and the maximum value was determined to be about 300 times the PFG’s own weight. Glassy carbon (GC) electrodes modified with the composite of GNPs and PFG (GNP−PFG composite) showed strong electrocatalytic activity and high electrochemical stability. A uric acid electrochemical sensor based on the composite modified electrode exhibited rapid response and high sensitivity.