Nanozyme‐Catalyzed Metasurface Plasmon Sensor‐Based Portable Ultrasensitive Optical Quantification Platform for Cancer Biomarker Screening

Developing plasmonic biosensors that are low‐cost, portable, and relatively simple to operate remains challenging. Herein, a novel metasurface plasmon‐etch immunosensor is described, namely a nanozyme‐linked immunosorbent surface plasmon resonance biosensor, for the ultrasensitive and specific detection of cancer biomarkers. Gold‐silver composite nano cup array metasurface plasmon resonance chip and artificial nanozyme‐labeled antibody are used in two‐way sandwich analyte detection. Changes in the biosensor's absorption spectrum are measured before and after chip surface etching, which can be applied to immunoassays without requiring separation or amplification. The device achieved a limit of alpha‐fetoprotein (AFP) detection < 21.74 fM, three orders of magnitude lower than that of commercial enzyme‐linked immunosorbent assay kits. Additionally, carcinoembryonic antigen (CEA) and carbohydrate antigen 125 (CA125) are used for quantitative detection to verify the universality of the platform. More importantly, the accuracy of the platform is verified using 60 clinical samples; compared with the hospital results, the three biomarkers achieve high sensitivity (CEA: 95.7%; CA125: 90.9%; AFP: 86.7%) and specificity (CEA: 97.3%; CA125: 93.9%; AFP: 97.8%). Due to its rapidity, ease of use, and high throughput, the platform has the potential for high‐throughput rapid detection to facilitate cancer screening or early diagnostic testing in biosensing.