Novel Double Z-Scheme ZnS/Bi <sub>2</sub> S <sub>3</sub> /Bi <sub>2</sub> Ti <sub>4</sub> O <sub>11</sub> Electrospun Heterojunction-Triggered Photocurrent-Polarity-Switching Cathodic Aptasensor for Fumonisin B1 Analysis
Qian Cao, Pengbo Niu, Rui Shi, Hang Gong, Yuchan Ma, Cheng Zhi Huang, Tong Yang
Abstract
High Resolution Image Download MS PowerPoint Slide Agricultural products are usually susceptible to mycotoxin contamination; the rapid and reliable detection of mycotoxins at the early stage is crucial for food safety. Here, a photocurrent-polarity-switchable cathodic photoelectrochemical (PEC) aptasensing platform was established for fumonisin B1 (FB1) analysis based on a novel ZnS/Bi 2 S 3 /Bi 2 Ti 4 O 11 (BTO) electrospun nanoheterojunction. Introducing S/Zn sources on Bi 4 Ti 3 O 12 electrospun nanofibers induced the component transformation of Bi 4 Ti 3 O 12 into BTO to generate ZnS/Bi 2 S 3 /BTO with double Z-scheme heterojunctions, thereby switching from anodic to cathodic photocurrent. On the photocathodic aptasensing interfaces of ZnS/Bi 2 S 3 /BTO, the FB1 aptamer-modified Au NPs/NiCo 2 O 4 as peroxidase-like mimics accelerate the oxidation of 4-chloro-1-naphthol in a H 2 O 2 environment to produce insoluble precipitates, quenching the photocathodic current with a 77.6% quenching efficiency. After incubation with FB1, the specific binding between FB1 and the aptamer could effectively reduce the catalytic sites of Au NPs/NiCo 2 O 4, resulting in the recovery of photocathodic current signals for the detection of FB1 with a linear range of 0.5 pg/mL–1000 ng/mL and a detection limit of 0.385 pg/mL. In a word, this work for the first time synthesized the novel ZnS/Bi 2 S 3 /BTO double Z-scheme electrospun heterojunctions as highly active photocathodic materials, offering a new perspective in the advancing polarity-switchable PEC bioanalysis.