Photoelectrochemical immunoassay of aflatoxin B 1 in foodstuff based on amorphous TiO 2 and CsPbBr 3 perovskite nanocrystals

• Published in: Analyst (London) 2019-08, Vol.144 (16), p.4880-4886
• Main Authors: Su, Lingshan, Tong, Ping, Zhang, Lijia, Luo, Zhongbin, Fu, Caili, Tang, Dianping, Zhang, Yuyu
• Format: Article
• Language: English
• Subjects: Aflatoxin B1 - analysis; Aflatoxin B1 - immunology; Alkaline Phosphatase - chemistry; Animals; Antibodies, Immobilized - immunology; Arachis - microbiology; Bromides - chemistry; Cattle; Cesium - chemistry; Electrochemical Techniques - instrumentation; Electrochemical Techniques - methods; Electrodes; Food Contamination - analysis; Immunoassay - methods; Lead - chemistry; Limit of Detection; Nanocomposites - chemistry; Nanoparticles - chemistry; Proof of Concept Study; Serum Albumin, Bovine - chemistry; Titanium - chemistry; Zea mays - microbiology
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/C9AN00994A

Aflatoxin B1 (AFB1) pollution is one of the most serious problems for food safety. In this paper, a split-type photoelectrochemical (PEC) immunoassay was designed for sensitive detection of AFB1 in foodstuffs by using amorphous TiO2 with all-inorganic perovskite CsPbBr3 nanocrystals (CsPbBr3/a-TiO2). The a-TiO2 layer not only improved the stability of CsPbBr3 nanocrystals, but also facilitated charge transfer, which resulted in the increasing photocurrent of the nanocomposites. Initially, a competitive-type enzyme immunoreaction was executed on a high-binding microplate between the analyte and alkaline phosphatase (ALP)-labeled AFB1-bovine serum albumin (AFB1-BSA) conjugate. Accompanied by the formation of the immunocomplex, the carried ALP triggered enzymatic hydrolysis to generate ascorbic acid (AA, as an electron donor) for increasing the photocurrent of the CsPbBr3/a-TiO2-modified electrode. Coupling with the competitive enzyme immunoassay, the photocurrent of the modified electrode decreased with the increase of target AFB1 concentration in a dynamic working range from 0.01 ng mL-1 to 15 ng mL-1 with a limit of detection (LOD) of 2.8 pg mL-1 under optimum conditions. Furthermore, the photoelectrochemical immunoassay was also utilized to detect AFB1 in peanut and corn samples, giving acceptable accuracy in comparison with the referenced AFB1 enzyme-linked immunosorbent assay (ELISA) method.