Biobased Synthesis of Gold Nanoparticles by Methanobactin

Abstract

Preparation of gold nanoparticles with a narrow size distribution has enormous importance in nanotechnology. Methanobactin (Mb) is a copper-binding small peptide that appears to function as an agent for Cu sequestration and uptake in methanotrophs. Mb can also bind and catalytically reduce Au (III) to Au (0). In the presence of hydroquinone as a electron donator, Mb can catalyze Au(Ⅲ) reduce to Au(0) and yield gold nanoparticles continuously. In this paper, a quantitative assay method for the content of Mb has been used. Continuous reduction of Au (III) by Mb can be achieved by using hydroquinone as the reducing agent. Effect of pH, reaction temperature, reaction time on Mb-mediated synthesis of gold nanoparticles was studied. The optimal conditions of gold nanoparticles synthesis were as follows: the optimum pH value was 5.1, the optimum reaction temperature was 40 ℃, the optimum reaction time was 15-20min. The gold nanoparticles are extremely stable and can resist aggregation, even after several months.