High Sensitive and Specific Detection of SCCA via Halloysite Nanotube Modified Terahertz Metasurface Sensor

Squamous cell carcinoma antigen (SCCA) level is an auxiliary indicator for lung cancer diagnosis and predictive monitoring, and its standard reference value is less than 1.5 ng/mL. Therefore, achieving high sensitivity and specific detection of the SCCA is a challenge. In this work, we designed a double split-ring-resonator (SRR) terahertz (THz) metasurface sensor. Simulation results show that the sensitivity of the sensor can reach 103 GHz/RIU (refractive index unit). After the sensor is modified with different concentrations of halloysite nanotubes (HNTs), the resonant frequency of the sensor exhibits different linear responses to different concentrations of SCCA. The optimum concentration of HNTs to enhance the detection performance of the sensor was obtained as 10 mg/mL. The linear range of SCCA concentration of the HNT modified sensor was 1 pg/mL to 100 ng/mL. On this basis, we modified anti-SCCA on the sensor, and other biomarkers of carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), CA125, and CA199 were used as comparisons. The results indicated that the sensor modified with HNTs showed a more remarkable frequency shift for the SCCA, which verified that the sensor had good specificity for the SCCA. Therefore, this sensor can be used for highly sensitive and specific detection of the SCCA.