Nanogap Dielectric Biosensor for label free DNA Hybridization detection

Abstract

Sensors based on nanogap capacitance changes are being developed for genomic and proteomic applications because they offer label-free detection on platforms amenable to high throughput configurations. This paper presents the development of fabrication and characterisation of lab-on-a-chip methodology for deoxyribonucleic acid (DNA) hybridization detection. The electrodes made of amorphous silicon (a-Si) separated by a narrow gap whose width is comparable to the size of a DNA molecule are used as a trap. During hybridization, trapped DNA change from single stranded DNA (ssDNA) to double stranded DNA (dsDNA) cause the change of charge density of molecules structure. This change results in an effective change of capacitance that can be monitored electronically by using dielectric spectroscopy, a type of impedance spectroscopy that measures the dielectric properties of a medium as a function of frequency.