A Nanomaterial-Independent Biosensor Based on Gallium Arsenide High-Electron-Mobility Transistors for Rapid and Ultra-Sensitive Pathogen Detection

Biofield effect transistors (bio-FETs) have emerged as promising candidates for next-generation pathogen detection platforms owing to their exceptional sensitivity and rapid response. However, they generally require complex electrical modulation strategies (e.g., nanomaterial-enhanced channels and external reference electrodes), which limits their practical applicability. Herein, we developed a structurally simplified Gallium–Arsenic-based high-electron-mobility transistor biosensor (GaAs-bioHEMT) fabricated through wafer-level processes, achieving an electron mobility of 7467.417 cm² V^–1 s^–1. This biosensor demonstrated effective detection of SARS-CoV-2 nucleocapsid protein (NP), reaching a detection limit of 0.125 fg mL^–1 within 5 min. Operating in depletion mode, the GaAs-bioHEMT design removes the requirement for nanomaterial modification and external reference electrodes. This strategy not only simplifies operational procedures but also shows compatibility with conventional semiconductor manufacturing processes, demonstrating great potential for point-of-care (POC) diagnostics and scalable clinical testing platforms.