Label-free photoelectrochemical immunosensor for aflatoxin B1 detection based on the Z-scheme heterojunction of g-C3N4/Au/WO3

• DOI: 10.1016/j.bios.2021.113373
• Publication Date: 2021-05-30T05:23:02Z
• Authors: Fubin Pei; Shasha Feng; Yi Wu; Xuchu Lv; Hualai Wang; Shen-Ming Chen; Qingli Hao; Yang Cao; Wu Lei; Zhaoyang Tong
• Keywords: Immunoassay; Aflatoxin B1; Limit of Detection; Animals; Metal Nanoparticles; Reproducibility of Results; Biosensing Techniques; Electrochemical Techniques; Gold; 01 natural sciences; 0104 chemical sciences

Aflatoxin B1 (AFB1) is the most toxic mycotoxin, is widely found in foods and animal feeds, and can pose a serious threat to our lives. A label-free photoelectrochemical (PEC) immunosensor was fabricated for the sensitive detection of AFB1. A Z-scheme heterojunction of gold nanoparticles (Au NPs) loaded on graphitic carbon nitride sheet and tungsten trioxide sphere composite (g-C3N4/Au/WO3) acted as the highly sensitive platform. The g-C3N4/Au/WO3 is capable, not only of immobilizing antibodies via Au NPs, but also enhancing the separation of electron-hole pairs due to its good energy band matching efficiency. The mechanism of photo-generated electron/hole transfer on g-C3N4/Au/WO3 was explored using scavengers to eliminate active components. On this basis, an electron transfer pathway for the immunosensor was deduced. The PEC immunosensor displayed a linear concentration range from 1.0 pg mL-1 to 100 ng mL-1 and a low detection limit of 0.33 pg mL-1 (S/N = 3) for AFB1. Good reproducibility, stability, and specificity provide a solid foundation for the practical application of this immunosensor.