Conducting polymer–metal hybrid materials have emerged as advanced platforms for electrochemical biosensing due to their high electrical conductivity, tunable surface characteristics, and versatile functionalization capabilities. In this study, we report the electrosynthesis of polypyrrole–silver (PPy–Ag) hybrid interfaces on glassy carbon electrodes as a foundation for biosensor development. Polypyrrole films were prepared via chronoamperometry at 1.3 V for 10 s, forming a uniform conductive matrix. Subsequently, silver nanoparticles were electrodeposited onto the PPy layer using pulsed potentials at −0.50 V for 3–5 s in an Ag₂SO₄/KSCN electrolyte, enhancing surface conductivity and catalytic activity. The resulting hybrid interfaces were thoroughly characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS), confirming the successful incorporation and uniform distribution of silver nanoparticles within the polymer matrix.

For biosensing applications, the antibodies Ki-67 (a cancer proliferation marker) and VP2 (a viral capsid protein) were covalently immobilized onto the PPy–Ag surfaces via Ag–NH₂ coordination under mild phosphate buffer conditions (pH 7.3). Electrochemical analyses revealed a notable increase in conductivity after silver incorporation and a significant reduction in current response upon antibody binding. This behavior suggests effective surface passivation and stable bio-recognition layer formation. Overall, the PPy–Ag hybrid platform offers a reproducible and adaptable approach for the development of sensitive electrochemical immunosensors targeting both oncological and virological biomarkers.