Synthesis of poly-Lysine/Gold nanoparticle films and their electrocatalytic properties

Abstract

Films composed of citrate stabilized gold nanoparticles (AuNPs) and Poly-Lysine (pLys) were fabricated by electropolymerization on glassy carbon (GC) electrodes from 0.1M phosphate buffer solution at pH = 8. The films were topographically analyzed by atomic force microcopy whereas their electrocatalytic properties were studied by cyclic voltammetry and electrochemical impedance spectroscopy in aqueous solution using 0.0005M [Fe(CN)6] 3-/4- as redox probes and 0.1M NaClO4 as supporting electrolyte. The electron transfer process proved to be more efficient at the pLys-AuNP modified electrodes containing low amounts of gold nanoparticles (500 µL, 2.5×10-4M) than at the bare glassy carbon electrode. The heterogeneous electron transfer constant increased 2 orders of magnitude at the pLys-AuNP modified electrodes proving a more efficient electron transfer than at bare GC. These new films have a great potential for DNA biosensor applications.