A procalcitonin photoelectrochemical immunosensor: NCQDs and Sb2S3 co-sensitized hydrangea-shaped WO3 as matrix through layer-by-layer assembly
Using nitrogen-doped carbon quantum dots (NCQDs) and antimony trisulfide (Sb2S3) to co-sensitize the hydrangea-shaped tungsten trioxide (WO3), a novel photoelectrochemical (PEC) immunosensor was constructed to sensitively detect procalcitonin (PCT). WO3 possessed three-dimensional structure with uniform size and large surface area on the indium tin oxide (ITO) electrode. NCQDs had abundant carboxy groups and exhibited excitation-independent PEC behavior which were modified on the surface of WO3 coating to enhance photochemical activity. Hence, the hydrangea-shaped WO3/NCQDs/Sb2S3 composite was obtained by modifying NCQDs and well-crystallized Sb2S3 nanoparticles on WO3 through layer-by-layer assembly. It was worth noticing that the photoelectric signal of WO3/NCQDs/Sb2S3 was about 8 times that of pure WO3 under visible light excitation. Moreover, the PEC immunosensor showed a large-scaled response (0.001-100 ng∙mL-1) and a low detection limit (0.42 pg∙mL-1) in the best experimental conditions. This PEC immunosensor has superiority such as simple, easy to make, high sensitivity and strong stability, which has good research value in the analysis and detection of disease biomarkers.