Supersandwich Nanowire/Quantum Dots Sensitization Structure-Based Photoelectrochemical “Signal-On” Platform for Ultrasensitive Detection of Thrombin
Xiaoshan Gao, Qianqian Cai, Hongkun Li, Guifen Jie
Abstract
A new photoelectrochemical (PEC) “signal-on” sensing platform based on photoactive material Bi2O3–ZnO and CdS quantum dots (QDs) sensitizer was fabricated for ultrasensitive determination of thrombin by constructing supersandwich nanowires. The CdS/ZnO/Bi2O3 sensitization structure with excellent energy level arrangement remarkably improved photoelectric conversion efficiency because of the efficient separation of the electron–hole. Moreover, the DNA supersandwich nanowire is ingeniously synthesized in one step by simple dislocation hybridization, which could carry a large amount of sensitized material CdS QDs. More importantly, with Exonuclease III (Exo III)-assisted multiple amplification, the proposed “signal-on” platform demonstrated a detection range of 10 fM to 1 μM with the detection limit of 1.41 fM for thrombin. Impressively, the PEC platform can successfully detect human serum samples with good accuracy. Above all, the CdS/ZnO/Bi2O3 sensitization photoelectric biosensing platform by using DNA nanowire in combination with Exo III-multiple amplification opens new sensitized amplification paths for supersensitive biosensing and bioanalysis.