Gold/mesoporous silica-fiber core-shell hybrid nanostructure: a potential electron transfer mediator in a bio-electrochemical system

Abstract

Mesostructured silica fibers synthesized by electrospinning silica sol were used as templates for the assembly of gold nanoparticles and the formation of continuous gold shells along the fiber axis. Dense and uniform spherical gold nanoparticles were formed by in situ reduction of hydrochloroauric acid absorbed on self-assembled polyelectrolyte film of silica fiber surface. The gold-seeded silica fibers were further coated by continuous gold shells via solution-phase reduction of an appropriate metal ion in PVP solution. The thickness and morphology of gold shell could be tailored by the molar ratio of repeating units of PVP to gold ions (R) and growth time. Experimental results showed that low R tended to form a thick gold layer with sharp tips, whereas high R favored obtaining thin and uniform Au shell. The SiO₂@Au fiber hybrid nanostructures are further used as substrates for fabrication of a glucose biosensor, which exhibited excellent bio-electrochemical activity with high sensitivity and rapid response. These hybrid nanostructures are, therefore, regard as molecule wires for potential application in highly sensitive chemical or biological sensors.