A DNA hybridization detection sensor based on photo biased ZnO thin film FET devices

Abstract

Purpose The purpose of this paper is to present a DNA hybridization detection sensor. An inexpensive fabrication procedure was used so that the sensors can be disposed economically after the measurement is completed. Design/methodology/approach Field effect transistor (FET) devices are used in the proposed structure. The FET device acts as a charge detection element and produces an amplified output current based on surface charge variations. As amplification is performed directly at the sensor frontend, noise sources have less effect on the detected signal, and thus, acceptably low DNA concentrations can be detected with simple external electronics. ZnO nano layers are used as the FET active semiconductor channel. Furthermore, a photobiasing approach is used to adjust the operating point of the proposed FET without the need for an additional gate terminal. Findings The proposed sensor is evaluated by applying matched and unmatched target DNA fragments on the fabricated sensors with capture probes assembled either directly on the ZnO surface or on a nano-platinum linker layer. It is observed that the presented approach can successfully detect DNA hybridization at the nano mole range with no need for complex laboratory measurement devices. Originality/value The presented photobiasing approach is effective in the adjustment of the sensor sensitivity and decreases the fabrication complexity of the achieved sensor compared with previous works.