Self-validating quasi-BIC Metasensors for reusable, ultrasensitive, and label-free biosensing.

The prevalence of prostate disease continues to rise, driving demand for efficient on-chip biosensors capable of early biomarker detection. This study proposed a novel biosensor based on a quasi-bound state in the continuum (QBIC), enabling multidimensional biomarker analysis. A One-step modification method using Parylene C facilitates antigen-antibody binding, with the potential for sensor reusability through Parylene C removal. The biosensor demonstrates high sensitivity, distinguishing varying concentrations of prostate-specific antigen (PSA) with a limit of detection (LOD) of 0.17 pg/mL by monitoring intensity changes. Our innovation sensing platform offers several advantages, including high sensitivity, reusability and a low detection limit, establishing a promising new approach for advanced biosensing applications. The proposed QBIC platform achieves high-performance sensing capability through concurrent spectral shift tracking and intensity modulation analysis, establishing a new paradigm for self-validating optical detection.