Direct Aerosol Detection of SARS-CoV-2 S Protein Using a Terahertz Metasurface Sensor Based on Bound States in the Continuum

Taking COVID-19 as an example, rapid screening and isolation of positive patients are crucial for preventing the spread of the virus. However, current technologies face challenges in terms of timeliness and accuracy. Emerging metasurface (MS) technology holds promise in addressing the issues. This paper presents an innovative method for detecting SARS-CoV-2 spike protein aerosols using advanced MS design and microfluidic technology. Through the Friedrich–Wintgen quasi-bound states in the continuum (F–W QBIC) theory, we designed an MS with a Q-factor of 23 and a sensitivity of 157.07 GHz/RIU. We also studied its resonant modes using multipolar expansion. Then, we designed an experimental microfluidic detection device to test the ability of the MS to detect alcohol solutions and SARS-CoV-2 S protein aerosols. The results show that, through quantitative simulation of a patient’s exhalation for 1 min, the device can detect SARS-CoV-2 S protein aerosols at a minimum detection limit of 0.1 ng/mL, with a sensitivity of 1.41 GHz/lg (ng·mL–1). Our research proposes a design, fabrication, and application method for a highly sensitive, low-detection-limit terahertz sensor for SARS-CoV-2 S protein aerosols. This provides a direct and innovative solution for real-time detection in infectious disease prevention and control.