Self-assembly of Gold Nanoparticles Using HPI S-layer Proteins Biotemplate

Bacterial cell-surface proteins (S-layer proteins) have an extremely repetitive surface structure well suited as a biotemplate to fabricate metallic/semiconducting nanostructures; an issue of high importance to the electronic industry. The surface layer proteins of Deinococcus radiodurans R1 (HPI) is an attractive S-layer for arraying nanoparticles. It illustrates hexagonal symmetry which is composed of a hexameric protein core unit with a middle hole. In this study, hexagonally structure of HPI protein was confirmed by AFM. Transmission electron microscopy and Fourier transform analysis revealed the formation of hexagonally ordered arrays of 4.5nm citrate-capped Au nanoparticles. Also, the influence of stability and dispersity of gold nanoparticles has been investigated on the fabrication of ordered arrays by nanoparticle’s zeta potential. The results reflect the effect of nanoparticles’ zeta potential value on the creation of their ordered arrays through HPI layer, which could be useful in using these ordered nanoarrays for fabricating bio-sensors and some electronic devices.