Nafion-Immobilized Functionalized MWCNT-based Electrochemical Immunosensor for Aflatoxin B1 Detection

Kai Deng; Yining Zhang; Hang Xiao; Yujiao Hou; Qingbin Xu; Ying Li; Weijun Kong; Li Ma

doi:10.1021/acsomega.3c04619

Nafion-Immobilized Functionalized MWCNT-based Electrochemical Immunosensor for Aflatoxin B₁ Detection

ACS Omega. 2024 Feb 13;9(8):8754-8762. doi: 10.1021/acsomega.3c04619. eCollection 2024 Feb 27.

Authors

Kai Deng^{1

2}, Yining Zhang^{1

2}, Hang Xiao¹, Yujiao Hou³, Qingbin Xu³, Ying Li³, Weijun Kong^{1

2}, Li Ma¹

Affiliations

¹ School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China.
² Laboratory for Clinical Medicine, Capital Medical University, Beijing 100069, China.
³ Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China.

Abstract

The ubiquitous aflatoxin B₁ (AFB₁) contamination in foods and other complex matrices has brought great challenges for onsite monitoring. In this study, an ultrasensitive Nafion-immobilized functionalized multiwalled carbon nanotube (MWCNT)-based electrochemical (EC) immunosensor was developed for trace AFB₁ detection. The introduced Nafion film could steadily stabilize functionalized MWCNTs with uniform distribution and tiling on the surface of a Au electrode. Functionalized MWCNTs with a large specific surface area, numerous active sites to couple with abundant anti-AFB₁ monoclonal antibodies (mAbs), and high conductivity served as the signal amplifier for remarkably enhancing the sensing performance of the immunosensor. In the presence of AFB₁, it was specifically captured by mAbs to reduce the amplified current signals, which were recorded by differential pulse voltammetry for the accurate quantitation of AFB₁. Because of the synergistic effects of Nafion on the stabilization of functionalized MWCNTs as signal enhancers, the developed EC immunosensor exhibited an extremely high selectivity, excellent sensitivity with a limit of detection as low as 0.021 ng/mL, and a wide dynamic range of 0.05-100 ng/mL, besides fascinating merits of easy construction, low cost, good stability in 7 days, and good reusability. The anti-interference ability of the immunosensor was verified against three other mycotoxins, and the practicability and accuracy were confirmed by measuring AFB₁ in fortified malt, lotus seed, and hirudo samples with a satisfactory recovery of 92.08-104.62%. This novel immunosensing platform could be extended to detect more mycotoxins in complex matrices to ensure food safety.