Nanozyme-strip based on MnO2 nanosheets as a catalytic label for multi-scale detection of aflatoxin B1 with an ultrabroad working range

Abstract

Lateral flow immunoassay (LFIA) is the most effective real-time detection method for aflatoxin B₁ (AFB₁). Here, we constructed a nanozyme-strip based on MnO₂ nanosheets (MnO₂ NSs) as a catalytic label for detection of AFB₁. By taking advantage of the MnO₂-TMB catalytic amplified system, the new test achieves rapid detection with high sensitivity and ultrawide range. The limit of detection of the assay was 15 pg mL^-1, which was over 100-fold lower than the maximum limit set by the European Union (EU) of AFB₁ in foods. In addition, the strip test could offer 7 dynamic detection ranges, spanning 4 orders of magnitude, which could cater to the varieties of limits on AFB₁ residues in foods and feeds set by different countries. The estimated recoveries were in the range of 85.67%-106.38% with coefficients of variations (CVs) less than 9.68%. Overall, the developed approach is a rapid, reliable, sensitive and widely available tool for on-site detection of AFB₁.

Keywords: Aflatoxin B(1); MnO(2) nanosheets; Multi-scale detection; Nanozyme; Oxidase mimic; Ultrabroad working range.