MnO2 nanoflowers based colorimetric and fluorescent dual-mode aptasensor for sensitive detection of aflatoxin B1 in milk

Abstract

Aflatoxin B1 (AFB1) with tremendous toxic effects has caused a serious threat to food security. Accurate quantification of AFB1 in food can effectively prevent the risk of human intake of AFB1. Herein, a colorimetric and fluorescent dual-mode aptasensor for accurate and sensitive detection of AFB1 has been developed based on MnO₂ nanoflowers (MnO₂NFs) for the first time. MnO₂NFs could catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) into blue oxidation product (TMBox) by H₂O₂, which would be used for visible detection of AFB1. Simultaneously, MnO₂NFs can be served as a signal amplifier and reduced by ascorbic acid to generate lots of Mn²⁺ which would quench the fluorescence of calcein for fluorescent detection of AFB1. Both colorimetric and fluorescent methods have been successfully applied for determination of AFB1 in milk samples with satisfactory results. The proposed dual-mode detection method with high detection sensitivity and accuracy showed great promise for monitoring AFB1 in food.

Keywords: Aflatoxin B1; Aptasensor; Dual-mode detection; MnO(2) nanoflowers.