A Low-Fouling Electrochemical Immunosensor Based On Metal–Organic Framework and Ternary Metal Oxide Nanomaterials Using Dual Signal Amplification Strategy for Sensitive Detection of Prostate-Specific Antigen (PSA) in Patient Samples

A label-free electrochemical immunosensor based on the zeolitic imidazolate framework-8 (ZIF8)/bismuth ferrite (BFO) nanocomposite was fabricated for the specific and sensitive quantification of prostate-specific antigen (PSA). The ZIF8-BFO material not only increases the surface area effectively but also enhances the catalytic capability of the electrode through a dual amplification strategy, leading to the improved sensitivity of the probe for PSA recognition. A thin layer of l-cysteine was used for two reasons: providing a scaffold for the next functionalization and reducing the fouling of plasma ingredients on the surface of the probe. The mechanical and spectroscopic properties of the produced nanomaterials were characterized using different techniques such as field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD), atomic force microscopy (AFM), the Fourier transform infrared (FTIR), and dynamic light scattering (DLS)/Zeta analyzer. The electroanalytical properties of the probe were studied using square-wave voltammetry (SWV) and cyclic voltammetry (CV). The signal of the probe decreased proportionally with increasing PSA concentration in the 100.0 pg/mL–15.0 ng/mL range, with a limit of detection (LOD) of 85 pg/mL. The proposed platform has been successfully employed to measure PSA levels in human serum samples with acceptable accuracy. The capability of the probe was evaluated in detecting PSA in patient's serum samples, with results compared to those obtained from the gold standard enzyme-linked immunosorbent assay (ELISA). The results suggested that the ZIF8-BFO material-based probe could be used as a promising method for detecting PSA and tracing therapy progression in clinics.