Aptamer-Linked Terahertz Meta-Sensor for Sensitive and Specific Detection of Carcinoembryonic Antigen

An aptamer-linked terahertz metamaterial sensor (ALT-Meta sensor) is presented for the sensitive detection of Carcinoembryonic Antigen (CEA), a biomarker of cancer in humans. The ALT-Meta sensor incorporates two symmetric split-ring resonators within a single unit cell, which boasts an exceptionally high quality (<i>Q</i>) factor of 20.4. Leveraging the silico SELEX method, we obtained a highly specific CEA-targeting aptamer (Seq >571) that significantly amplifies the sensor's sensitivity while maintaining its remarkable specificity. Experimental results demonstrate that the ALT-Meta sensor exhibits a robust response to CEA concentrations ranging from 0.1 to 100 ng/mL, with a detection limit as low as 13 pg/mL, which is an order of magnitude lower than that of traditional antibody-based sensors. Its simplicity, stability, and cost-effectiveness make it a highly efficient platform for accurate CEA detection, advancing early cancer diagnostics.