Dual-Mode Photoelectrochemical and Electrochemical Immunosensors for Human Epididymis Protein 4 Based on SPR-Promoted Au Nanoparticle/CdS Nanosheet Heterostructures

As a promising biomarker, human epididymis protein 4 (HE4) shows wide applications for early diagnosis and therapy of ovarian cancer. Herein, heterostructured Au nanoparticles/CdS nanosheet (Au NPs/CdS NS) were initially constructed by two-step electrodeposition and used to build photoelectrochemical (PEC) and electrochemical (EC) dual-mode immunosensors for the detection of HE4. As one of appealing properties, surface Plasmon resonance (SPR) effects of Au NPs endowed the Au NPs/CdS NS heterostructures with highly enhanced PEC and EC signals upon light irradiation, which were gradually weakened by elevating the HE4 concentrations. Under the optimal conditions, the dual-mode sensor displayed wider linear ranges of 0.01–100 and 0.01–200 ng mL–1 for PEC and EC modes, respectively. The detection limits were 1.084 and 1.188 pg mL–1 for PEC and EC detections, respectively. This sensing platform holds great potential for the analysis of other biomarkers in the clinical field.