Biosilica structures with controllable morphology produced by an electrochemical process on indium tin oxide surfaces

Abstract

In this paper, the formation of stable and continuous inorganic coating on indium tin oxide (ITO) via biosilica polymerization in the presence and absence of externally imposed electrostatic fields is described. The electrostatic fields exert a stronger influence on poly-L-lysines (PLLs) with a lower molecular weight than on larger ones. The larger peptides only enhance the density and uniformity of the biosilica deposition, whereas the overall biosilica morphology is observed to shift from sphere- to club-like structures when smaller PLLs are used. To explore the biosilica formation mechanism under precisely controlled electrostatic fields, scanning electron microscopy, circular dichroism, and atomic force microscopy were used to investigate the process of polypeptide tailored silica precipitation. Our results indicated that electric fields result in a high concentration of polypeptide near the ITO surfaces, which can be used as organic templates and basic building blocks to provide opportunities for tailoring material morphologies.