By integrating a receptor cavity interaction layer, an optical source, a waveguide, and an array of detectors, all on-chip, this proposed design aims to demonstrate the viability of a nanomaterial-enhanced silicon photonic-biosensor architecture optimized for label-free detection of PSA as a next-generation diagnostic tool for prostate cancer, with the potential to improve early detection, reduce false positives, and streamline clinical workflows. The gene discussed is KLK3; the disease is prostate cancer.