Detection of specific single-stranded DNA molecules through SiNW surface modulation

Abstract

This paper demonstrate a silicon nanowire biosensor for the detection of specific ssDNA biomarker detection. The biosensor was fabricated using conventional photolithography coupled with an inductively coupled plasma dry etching process. The detection was performed with a semiconductor parameter analyzer which measured the changes in current and conductance of the nanowire electrodes upon target DNA hybridization. The sensor surface was silanized and directly aminated with (3-aminopropyl)triethoxysilane to create a molecular binding chemistry for bio-functionalization. The resulting Si---O---Si-components were functionalized with receptor ssDNA, which interacted with the targeted ssDNA to create a field across the silicon nanowire and increase the current. Hybridization detection discrimination among various concentration, the device response to the targets shows selectivity for the ssDNA in a linear range from ssDNA concentrations of 100 pM to 150 nM. Linearity of the device to molecular concentration, was confirm linear fit curve for the (0.1---0.5) nM concentration and (0---40) nM concentration.