Ultrasensitive split-type photoelectrochemical immunoassay with interfacial hole-dynamic regulation via nitrogen-doped carbon hole transport layer in α-Fe(2)O(3)/CN/NiFe-LDH ternary photoanode.

内容摘要

Integrating a hole transport layer (HTL) into photosensitive materials is a well-established strategy to bolster photoelectrochemical (PEC) performance, as it facilitates efficient charge carrier separation and directional migration. Herein, an innovative split-type PEC immunosensing platform based on ternary α-Fe2O3/CN/NiFe-layered double hydroxide (LDH) hierarchical architectures was strategically engineered. In this framework, nitrogen-doped carbon (CN) served as the HTL, establishing a high-efficiency charge extraction channel between the α-Fe2O3 core and the NiFe-LDH cocatalyst, which significantly suppressed non-radiative recombination. Following the specific immunorecognition of carcinoembryonic antigen (CEA), enzymatically generated H2O2 was introduced into the PEC cell as a potent hole scavenger to markedly augment the photocurrent signal. The resulting PEC immunosensor exhibited exceptional sensitivity and selectivity, with a wide linear range from 0.02 ng mL-1 to 50 ng mL-1 and a low detection limit of 7.21 pg mL-1. This work offers critical insights into the design of high-performance hole-transporting interfaces and the development of PEC sensing platforms for clinical diagnostics.