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.
Hepatocellular carcinoma is a life-threatening malignant tumor found around the world for its high morbidity and mortality. Therefore, it is of great importance for sensitive analysis of liver cancer cells (HepG2 cells) in clinical diagnosis and biomedical research. To fulfill this demand, hollow CdIn 2 S 4 /In 2 S 3 heterostructured microspheres (termed CdIn 2 S 4 /In 2 S 3 for clarity) were prepared by a two-step hydrothermal strategy and applied for building a novel photoelectrochemical (PEC) cytosensor for ultrasensitive and accurate detection of HepG2 cells through specific recognition of CD133 protein on the cell surface with the respective aptamer. The optical properties of CdIn 2 S 4 /In 2 S 3 were investigated by UV−vis diffuse reflectance spectroscopy (DRS) and PEC technology. By virtue of their appealing PEC characteristics, the resultant PEC sensor exhibited a wider dynamic linear range from 1 × 10 2 to 2 × 10 5 cells mL −1 with a lower limit of detection (LOD, 23 cells mL −1 ), combined by evaluating the expression level of CD133 protein stimulated by metformin as a benchmarked inhibitor. This work opens a valuable and feasible avenue for sensitive detection of diverse tumor cells, holding great potential in early clinical diagnosis and treatment coupled by screening inhibitors.
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