Electrical detection of femtomolar DNA via gold-nanoparticle enhancement in carbon-nanotube-network field-effect transistors

Abstract

A significant sensitivity enhancement in electrical detection of DNA hybridization in SNFETs through the introduction of reporter DNA-AuNP conjugates in the hybridization step was investigated. The amplified change in drain current allowed to reliably determine the DNA concentration down to ca. 100 fM. Random networks of SWNTs with diameters between 1 and 3 nm and lengths between 5 and 10 μm were first grown onto SiO wafers using chemical vapor deposition techniques. SWNT network transistors (SNFETs) were fabricated in a top-contact device geometry, where 30 nm of a Ta electrodes were patterned on top of it by using standard lithography techniques. It was observed that SNFET-based biosensors and immunosensors may be adapted to detection of a variety of biomarkers for applications ranging from molecular diagnostics to in vitro diagnostics. 2