Photoelectrochemical immunoassay platform based on MoS2nanosheets integrated with gold nanostars for neuron-specific enolase assay

MoS(2)nanosheets were prepared by exfoliating MoS(2)bulk crystals with ultrasonication in N-methylpyrrolidone and were integrated with gold nanostars (AuNS) to fabricate an AuNS/MoS(2)nanocomposite. All nanomaterials were characterized by transmission electron microscope, scanning electron microscope, ultraviolet-visible spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. AuNS/MoS(2)nanocomposites were coated onto a glassy carbon electrode (GCE) surface to construct a nanointerface for immobilizing neuron-specific enolase antibody (anti-NSE) thus forming a photoelectrochemical immunoassay system. AuNS can significantly promote the photoelectric conversion of MoS(2)nanosheets improving the performance for a photoelectrochemical assay. Being illuminated with white light LED and controlling the potential at 0.05 V (vs. SCE), the photocurrent generated from anti-NSE(BSA)/AuNS/MoS2/GCE using 0.15 mol L(-1)ascorbic acid as electron donor can be recorded with amperometry and used as an output signal for NSE quantitative assay. Under optimized experimental conditions, the photocurrent variation for the affinity-binding NSE is proportional to the logarithm of NSE concentration in the range 5.0 pg mL(-1) to 1.5 ng mL(-1)with a detection limit of 3.5 pg mL(-1)(S/N = 3). The practicability of the PEC immunoassay system was evaluated by determining NSE in clinical serum samples. The recoveries ranged from 93.0 to 103% for the determination of NSE in serum samples with a standard addition method. The PEC immunoassay system possesses good accuracy for determining NSE in real samples. Graphical abstract