Attogram per milliliter detection of prostate cancer biomarker using polymer dots-based electrolyte-gated organic...

Early detection of biomarkers in body fluids plays a critical role in the diagnosis and prognosis of prostate cancer, the second most common cancer in men. In this study, we synthesized novel semiconducting polymer dots (Pdots) to serve as the channel material in electrolyte-gated organic field-effect transistors (EGOFET) for the ultrasensitive detection of PSA antigen, a key cancer biomarker. To fabricate the active channel material, Pdots were drop-cast onto the FET surface, and the surface was subsequently functionalized with PSA antibodies. The Pdot EGOFET immunosensor demonstrated the ability to detect PSA antigen across a concentration range of 10 ag/mL to 10 ng/mL, with a significant decrease in drain current (I_ds) and a high sensitivity of 0.9097 μA/decade. The sensor exhibited a limit of detection (LOD) of 3.0 ag/mL. Furthermore, the Pdot EGOFET immunosensor displayed remarkable electrical characteristics, including a mobility of 0.029 cm²V^-1s^-1, an on/off current ratio of 22.66, and a subthreshold swing (SS) of 909.1 mV/decade. Additionally, the sensor demonstrated excellent selectivity, with its performance being compared favorably to an enzyme-linked immunosorbent assay (ELISA) for detecting PSA in spiked human serum samples. The positive and promising results of this study indicate that the developed Pdot EGOFET immunosensor holds significant potential as a highly effective platform for cancer diagnosis and therapeutic monitoring.