AUTHOR=Feng Kai , Di Ya , Han Meng , Yan Weitao , Guo Yulin , Huai Xiangqian , Wang Yimin TITLE=A photoelectrochemical aptasensor based on double Z-scheme α-Fe2O3/MoS2/Bi2S3 ternary heterojunction for sensitive detection of circulating tumor cells JOURNAL=Frontiers in Bioengineering and Biotechnology VOLUME=12 YEAR=2024 URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2024.1372688 DOI=10.3389/fbioe.2024.1372688 ISSN=2296-4185 ABSTRACT=

A novel photoelectrochemical (PEC) aptasensor based on a dual Z-scheme α-Fe₂O₃/MoS₂/Bi₂S₃ ternary heterojunction for the ultrasensitive detection of circulating tumor cells (CTCs) was developed. The α-Fe₂O₃/MoS₂/Bi₂S₃ nanocomposite was prepared via a step-by-step route, and the photoproduced electron/hole transfer path was speculated by conducting trapping experiments of reactive species. α-Fe₂O₃/MoS₂/Bi₂S₃-modified electrodes exhibited greatly enhanced photocurrent under visible light due to the double Z-scheme charge transfer process, which met the requirement of the PEC sensor for detecting larger targets. After the aptamer was conjugated on the photoelectrode through chitosan (CS) and glutaraldehyde (GA), when MCF-7 cells were presented and captured, the photocurrent of the PEC biosensing system decreased due to steric hindrance. The current intensity had a linear relationship with the logarithm of MCF-7 cell concentration ranging from 10 to 1×10⁵ cells mL⁻¹, with a low detection limit of 3 cell mL⁻¹ (S/N = 3). The dual Z-scheme α-Fe₂O₃/MoS₂/Bi₂S₃ ternary heterojunction-modified PEC aptasensor exhibited high sensitivity and excellent specificity and stability. Additionally, MCF-7 cells in human serum were determined by this PEC aptasensor, exhibiting great potential as a promising tool for clinical detection.