Photochemical Growth of Highly Densely Packed Gold Nanoparticle Films for Biomedical Diagnostics

Abstract

Utilizing ultraviolet photochemical reduction of gold(III) chloride trihydrate (HAuCl4), a new kind of synthesis of a highly dense gold nanoparticle film on a p-type silicon wafer was conducted. Through scanning electron microscopy and atomic force microscopy, the gold nanoparticle film was confirmed to be 90 nm thick, with an average gold nanoparticle size of 125 nm in diameter. To explore applications in surface enhanced Raman spectroscopy (SERS), a protein model of streptavidin and pegylated biotin functionalized to the surface of gold nanoparticle films was employed. Observations indicate that there was a proximity induced excitation of localized surface plasmons due to the densely packed gold nanoparticle film. Excitation of the localized surface plasmons leading to hot spots of SERS activity on the gold nanoparticle film allowing it to act as an eco-friendly and highly sensitive SERS substrate for biomedical diagnostic applications.