Fabrication of conducting polymer micro/nanostructures coated with Au nanoparticles for electrochemical sensors.

Polypyrrole (PPy) micro/nanostructures coated with Au nanoparticles were prepared by electropolymerization and electro-deposition. Two types of PPy structures, micro-embossed and nanowire forest, were synthesized on patterned gold electrodes using different aqueous solutions, and Au nanoparticles were coated onto the PPy micro/nanostructure surface. The size of the Au nanoparticles ranged from 10 to 100 nm, and the maximum density of the nanoparticles was 73 particles/microm2. The small size and high density of the Au nanoparticles were achieved by optimizing the deposition time and chloroauric acid (HAuCl4) concentration. Cyclic voltammograms of ferrocyanide oxidation showed that the PPy micro/nanostructures coated with Au nanoparticles exhibit good electrochemical activity. These high-performance electrodes can be used in electrochemical sensors because the Au nanoparticles enhance electron transfer and provide a binding site for biomarker molecules, such as DNA, protein, and aptamers.