# A Highly Sensitive Silicon Nanowire Array Field Effect Transistor Biosensor for Detecting HBV-DNA and AFP

## TL;DR

This paper introduces a new biosensor that can detect two key biomarkers for chronic hepatitis B with high sensitivity and low cost, enabling early diagnosis.

## Contribution

A novel silicon nanowire array FET biosensor for joint detection of HBV-DNA and AFP with ultralow detection limits.

## Key findings

- The SiNW-array FET biosensor achieved detection limits of 0.1 fM for HBV-DNA and 0.1 fg/mL for AFP.
- The biosensor demonstrated good linearity across a wide range of HBV-DNA and AFP concentrations.
- Successful detection of HBV-DNA in serum samples was achieved, showing potential for clinical use.

## Abstract

Chronic hepatitis B poses a serious threat to human health and life, and early diagnosis is essential to improving patient cure rates. Hepatitis B virus (HBV) and Alpha-fetoprotein (AFP) are two key biomarkers for diagnosing chronic hepatitis B. In this study, we propose a silicon nanowire array field effect transistor (SiNW-array FET) biosensor that enables highly sensitive, real-time, and low-cost joint detection of both HBV and AFP. The SiNW-array FET is fabricated using traditional micro-nano fabrication techniques such as self-limiting oxidation and anisotropic etching, and its morphology and electrical properties were tested. The results show that the diameters of the fabricated silicon nanowires (SiNWs) are uniform and the SiNW-array FET exhibits a strong output signal and high signal-to-noise ratio. Through specific chemical modification on the surface of SiNWs, the SiNW-array FET is highly sensitive and specific to HBV-DNA fragments and AFP, with ultralow detection limits of 0.1 fM (HBV-DNA) and 0.1 fg/mL (AFP). The detection curve of the SiNW-array FET exhibits good linearity within the HBV-DNA concentration range of 0.1 fM to 100 pM and AFP concentration range of 0.1 fg/mL to 1000 pg/mL. More importantly, the device could also detect HBV-DNA successfully in serum samples, laying a solid foundation for the highly sensitive clinical detection of chronic hepatitis B.