Application of a Calibration Method for the Saturation Response in PSA Detection of Silicon Nanowire Sensors

Detecting low-abundance prostate-specific antigen (PSA) in complex fluids is a diagnostic challenge, requiring ultra-sensitive, consistent sensors. Silicon nanowire (SiNW) field-effect transistor (FET) biosensors offer label-free, ultra-sensitive detection but suffer from sensor-to-sensor inconsistencies. In this paper, we apply a saturation response calibration method to PSA detection, improving sensor consistency by normalizing results based on the saturation response (Ssat), which overcomes variations in feature sizes and surface functionalization. After calibration, the coefficient of variation (CV) decreased by 41.3–95.8%, significantly enhancing sensor consistency. PSA was detected rapidly (within 6 min) across a dynamic range of 0.1 pg/mL–1 μg/mL. This work has, to some extent, promoted the transformation of SiNW FET biosensors from theoretical research to practical application.