A strategy to minimize the sensing voltage drift error in a transistor biosensor with a nanoscale sensing gate

Abstract

Hyun Woo Son,1,* Minhong Jeun,1,* Jaewon Choi,1,2 Kwan Hyi Lee1,2 1Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology, Seoul, 2Department of Biomedical Engineering, Korea University of Science and Technology, Daejeon, Republic of Korea *These authors contributed equally to this work Abstract: An ion-sensitive field-effect transistor (ISFET) biosensor is thought to be the center of the next era of health diagnosis. However, questions are raised about its functions and reliability in liquid samples. Consequently, real-life clinical applications are few in number. In this study, we report a strategy to minimize the sensing signal drift error during bioanalyte detection in an ISFET biosensor. A nanoscale SnO2 thin film is used as a gate oxide layer (GOL), and the surface of the GOL is chemically modified for improving bioanalyte-specific binding and for reducing undesirable ion reactions in sample solutions. The ISFET biosensor with surface-modified GOL shows significantly reduced sensing signal error compared with an ISFET with bare GOL in both diluted and undiluted phosphate buffered saline solutions. Keywords: extended gate, surface treatment, biosensor, SnO2, ISFET

Keywords

• Biosensor
• transistor
• SnO2
• voltage Drift
• sensing gate