Label-free electrochemical immunoassay for ultra-sensitive detection of PSA utilizing gold nanoparticles/polyhedral hollow CoCu bimetallic sulfide nanostructure as a dual signal amplification platform.

This study introduces the development of a highly sensitive label-free electrochemical immunosensor specifically designed to detect prostate-specific antigen (PSA). A glassy carbon electrode (GCE) coated with Au nanoparticles/polyhedral hollow CoCu bimetallic sulfide (CuCo₂S₄) was employed as a sensing interface for the fixation of the monoclonal anti-PSA antibody. The nanoarchitectures enhanced the capacity for loading prostate-specific antibodies (Ab) and effectually boosted electrical conductivity leading to enhance the electrochemical signal and greater sensitivity for the detection of PSA. The electrochemical behavior of the engineered sensor was researched via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The response of the fabricated immunosensor manifested a linearized correlation with PSA concentration, spanning from 50.0 fg/ml to 500.0 ng/ml, with a minimal detection limit (DPV: 19.0 fg/ml, EIS: 14.0 fg/ml) and superior stability. The morphological and structural features of the engineered nanomaterials were analyzed using a range of techniques, including field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The proposed immunosensor was utilized for the meticulous and ultra-sensitive analysis of PSA levels in serum specimens, providing results that align satisfactorily with those from the enzyme-linked immunosorbent assay (ELISA) the benchmark protocol. In conclusion, these outcomes underscore the potential utility of the developed immunosensor for prostate cancer screening in its initial stages.