Highly Sensitive Zr-MOF-Amplified Electrochemical Immunosensor of Prostate-Specific Antigen with MWCNTs/AuNPs/MnO ₂ Nanocomposites

Prostate cancer remains one of the most prevalent malignancies affecting men worldwide. Early diagnosis plays a critical role in improving patient outcomes, with the measurement of prostate-specific antigen (PSA) levels in human serum analysis serving as a key strategy for early detection. In this study, we report the development of an ultrasensitive, label-free electrochemical immunosensor for the specific detection of PSA in human serum samples, achieved through multistep signal amplification via electrode layering with conductive nanomaterials. The innovative strategy involves electropolymerization of sodium alginate (NaAlg) onto glassy carbon electrodes (GCEs), followed by surface modification with nanocomposites composed of multiwalled carbon nanotubes, gold nanoparticles, and manganese dioxide (MWCNTs/AuNPs/MnO₂), which enhanced electron transfer kinetics and provided a high-surface-area matrix for dense and stable immobilization of PSA antibodies. In addition, zirconium-metal-organic frameworks (Zr-MOFs) were utilized as a secondary amplification element for further sensitivity enhancement. The immunosensors exhibited a broad linear dynamic range of 100 fg/mL to 1 ng/mL, with a low limit of detection (LOD) of 5 fg/mL. Moreover, the immunosensor demonstrated outstanding performance in detecting trace levels of PSA in human serum, including a broad dynamic detection range (40 dB), high sensitivity, excellent stability over 15 days, and strong selectivity, with promising potential for clinical diagnostics and the early detection of prostate cancer.