Ni3V2O8-MnV2O6@Poly(p-toluidine) nanocomposite-based disposable electrochemical immunosensing platform for ultrasensitive detection of Candida albicans.

A label-free, electrochemical portable immunosensing system was designed for the rapid, selective, and sensitive detection of Candida albicans. The sensor is based on a novel organic-inorganic hybrid nanocomposite comprising one-dimensional MnV2O6, three-dimensional Ni3V2O8, poly (p-toluidine) (PpT), and gold nanoparticles (AuNPs), integrated onto a screen-printed electrode via covalent immobilization of anti-C. albicans antibody for oriented and stable capture of candida cells. This study reports the first integration of PpT with bimetallic vanadates for fungal biosensing, establishing a structure-function-driven electron-transfer network that enables ultrasensitive, label-free, and matrix-free detection of C. albicans directly in urine without pretreatment. The nanocomposite formation and biofunctionalization were characterized by FTIR, Raman, XRD, XPS, HRTEM, SAED, SEM, EDX, and zeta potential analyses in order to identify all acquired features by the nanocomposite. Under optimized conditions, the immunosensor exhibited a wide linear dynamic range of 1.0-106 CFU/mL and an ultra-low detection limit of 0.29 CFU/mL. The platform demonstrated excellent selectivity against common non-targeting organisms, high reproducibility (RSD 2.1%), robust stability (93% signal retention), and negligible matrix effects, with recoveries of 103-105% in spiked-urine samples without any pretreatment. This disposable and portable immunosensing system presents a powerful tool for point-of-care candiduria screening, enabling rapid and reliable clinical intervention.