Colorimetric immunoassay via smartphone based on Mn2+-Mediated aggregation of AuNPs for convenient detection of fumonisin B1

Abstract Fumonisin B1 (FB1) is one of the most toxic and widely distributed subtypes of the 20 fumonisins, which has attracted much attention in food and feed safety. In this study, a convenient colorimetric immunoassay was proposed for the detection of FB1 based on Mn2+-mediated aggregation of gold nanoparticles (AuNPs). After hydrolyzing of ascorbic acid 2-phosphate (AAP) by alkaline phosphatase (ALP), the generated ascorbic acid (AA) decomposes brown MnO2 shell to Mn2+, which growth onto AuNPs and inducing the aggregation of AuNPs. The color change of the solution induced by aggregating of AuNPs can be read by smartphone to avoid subjective differences. The limit of detection (LOD) of this assay was 0.15 ng/mL and the limit of quantification (LOQ) was 0.50 ng/mL. The method has not cross-reaction with other mycotoxins. The average recoveries of FB1 in the maize flour samples ranged from 86.4 % to 110.9 %, which met the food and Drug Administration (FDA) restrictions on FBS in agricultural products. The colorimetric immunoassay can be potentially used for mycotoxin-related food safety monitoring.