High-Sensitivity Tunable Terahertz Metasurface Based on Vanadium Dioxide for Biological Protein Detection

Terahertz (THz) metasurface sensors hold significant potential for detecting ultralow concentration of various target biomarkers, offering a powerful platform for bioanalysis and disease marker diagnostics. Most existing THz metasurface sensors are passive, providing high measurement precision, though their accuracy can be further improved. This study proposes a tunable THz metasurface sensor based on electromagnetically induced transparency (EIT) with vanadium dioxide (VO₂) as a functional material. The designed metasurface arrays feature adjustable resonant modes at frequencies of 0.5 THz and 0.75 THz, achieving sensitivities of 0.08 THz/RIU and 0.11 THz/RIU, respectively. This sensor demonstrates excellent performance in detecting ultralow concentrations of biomarker proteins and enables different detection modes by controlling the phase transition of VO₂, ensuring stability through cross-validation of experimental results. Experimental testing shows the sensor’s sensitivity to hemoglobin and glycated hemoglobin, with a detection limit as low as 10 pM. The dual detection modes confirm the accuracy of experimental results, supporting diverse applications for low-concentration THz biosensing and enhancing the practical utility of THz sensors.