Development of Resistive Biosensors for Detection of SPINK-1 Protein

Prostate cancer is among the leading cancer-related deaths in men worldwide, with early and accurate detection playing a pivotal role in improving treatment outcomes. Current clinical diagnostics suffer from low specificity and sensitivity, often leading to unnecessary invasive diagnosis procedures. This research presents the development of a resistive biosensor for the detection of SPINK-1, a biomarker strongly associated with aggressive prosta1te cancer subtypes. The biosensor leverages reduced graphene oxide (RGO) decorated with gold nanoparticles (AuNPs) as the transducer layer and monoclonal antibodies (mAB) of SPINK-1 for detecting 0.001 to 100 ng/mL of SPINK-1 antigen. The optimized sensor devices yielded responses ranging from 1.66 to 34.51% for 0.001 to 100 ng/mL SPINK-1. The RGO/AuNP/mAB sensors were also found to exhibit excellent selectivity when tested with other cancer biomarkers like PSA, CA125, and CEA. Detailed material characterization using field emission scanning electron microscope (FESEM), energy-dispersive spectroscopy (EDS), and ultraviolet-visible spectroscopy confirmed the successful functionalization of the sensor and binding of the antigens and antibodies.