Rapid SARS-CoV-2 Detection Using High-Sensitivity Thickness Shear Mode Sensors

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has emphasized the urgent need for accurate and readily available diagnostic tools. Conventional diagnostic methods, such as reverse transcription real-time polymerase chain reaction (RT-qPCR), are often labor-intensive and time-consuming, which highlights the necessity for rapid point-of-care diagnostic solutions. This study introduces an innovative, low-cost, and highly sensitive diagnostic platform for swift COVID-19 detection. Our platform utilizes the mass sensing properties of thickness shear mode (TSM) transducers to detect and quantify the SARS-CoV-2 nucleocapsid protein through polyethylene glycol (PEG)-based chemistry (1). To confirm surface functionalization and evaluate the effects of the virus lysis buffer, we employed surface characterization techniques including Digital Holographic Microscopy (DHM), Scanning Electron Microscopy (SEM) with Energy-Dispersive X-ray spectroscopy (EDX), and Raman spectroscopy. Sensitivity tests with heat-inactivated SARS-CoV-2 samples demonstrated a sensitivity of about 0.256 Hz/TCID50/mL and a limit of detection (LOD) of roughly 150 TCID50/mL. Specificity was verified through cross-reactivity testing. Our detailed characterization and sensitivity analysis underscore the platforms reliability, making it a promising candidate for efficient and accessible COVID-19 diagnosis at the point of care.