Top-Down Fabrication of Silicon Nanogap for Detection of Dengue Virus (DENV)

Abstract

In this work, a highly sensitive Silicon nanogap biosensor was demonstrated for Deoxyribonucleic acid (DNA) detection related to Dengue virus (DENV). The Silicon nanogap was fabricated using the top–down conventional lithography approach followed by reactive ion etching (RIE) to further thin down the nanogap. The inspections of Silicon nanogap structures were carried out using the scanning electron microscope (SEM) and atomic force microscopy (AFM). The surface of the fabricated Silicon nanogap was functionalized by means of a three-steps procedure involving surface modification, immobilization and hybridization. This procedure acts as a liquid gate control to establish the electrical detection targets of the dengue virus. The electrical detection is based on the changes in the current of the sensor due to the accumulation of the negative charges by the immobilized probe and hybridized target Deoxyribonucleic acid. The limit of detection (LOD) achieved was recorded at 10 pM with a 207 nm of fabricated Silicon nanogap and its sensitivity at 1.5 × 10⁻¹⁰ AM⁻¹. The demonstrated results show that the Silicon nanogap has the excellent properties for detection of dengue virus as biosensor devices.