Establishment Of Immunoassays Based On MnO₂ Nanosheet For Fumonisin B1 In Maize

Establishment of Immunoassays Based on Mn O₂ Nanosheet forFumonisin B1 in MaizeFumonisin is a water-soluble secondary metabolite produced by Fusarium moniliforme shell,Fusarium verticillioides and other fusarium species,which may contaminate corn,wheat,rice and other food crops all over the world.Fumonisin has immunotoxicity,neurotoxicity and organotoxicity.It is a class 2B carcinogen recognized by the international agency for research on cancer(IARC)and is related to liver cancer,kidney cancer and esophageal cancer.Among several common fumonisin,fumonisin B1(FB1)is the most toxic and widely distributed.Therefore,the research on ultra-sensitive detection methods of FB1 is urgent demand for food safety and the health of consumers.Mn O₂ nanosheet is a new nano material widely used in the field of biosensors.It has strong fluorescence quenching ability,oxidation ability,catalytic activity and good biocompatibility.In this study,two rapid and efficient immunological detection methods of FB1 were established based on FB1 monoclonal antibody and Mn O₂ nanosheet.The details are as follows:1.An indirect competitive ELISA(ic-ELISA)was established.The regression equation of standard curve was Y=37.869 X+14.319,and the correlation coefficient(R~2)was 0.97.The detection range(IC₂₀?IC₈₀)was 1.41?54.25 ng/m L,and the LOD(IC₁₀)was 0.77 ng/m L.The cross reaction rates with FB2 and FB3 were 5.60%and18.10%respectively,and the cross reaction rates with other mycotoxins were less than0.10%.The recovery rate was 93.04%?116.32%,which was in line with the regulations of the American Association of Analytical Chemistry(AOAC).Compared with the results between the developed ic-ELISA and commercial ELISA kit,the correlation coefficient(R~2)was 0.99.2.A plasmonic enzyme-linked immunosorbent assay(p-ELISA)was established based on Au NPs and Au NP@Mn O₂,which can read the test results directly through smartphone.The regression equation of the standard curve is:Y=21.947 X–14.752,and the correlation coefficient(R~2)is 0.96.The detection range is 6.26?200 ng/m L and LOD is 0.15 ng/m L.The recovery rate is 86.36%?110.90%,which meets the provisions of AOAC.The correlation coefficient(R~2)was 0.98 compared with the results of standard addition and recovery of commercial ELISA kit.3.Based on the characteristics that o-phenylenediamine(OPD)can be oxidized into yellow fluorescent substance 2,3-diaminophenazine(DAP)by Mn O₂ nanosheet and reduced to blue fluorescent substance quinoxaline(OPDred)by dehydroascorbic acid(DHAA),a fluorescence ratio immunoassay was established.The regression equation of standard curve is:Y=-0.088 X+0.197,and the correlation coefficient(R~2)is 0.99.The detection range is 0.25?60 ng/m L.LOD was 0.06 ng/m L.The recovery rate is 76.93%?100.98%,which meets the provisions of AOAC.The correlation coefficient(R~2)is 0.99 compared with the results of standard addition and recovery experiment of commercial kit.In this study,three immunoassays for FB1 were established.The ic-ELISA has the advantages of simple operation,good repeatability,high throughput and no need for special instruments.The p-ELISA was established based on decomposition of Au NP@Mn O₂ and aggregation of Au NPs.This method is easy to operate and can be applied to field detection.The sensitivity is better than that of ic-ELISA.The fluorescence ratio immunoassay was established based on oxidase activity of Mn O₂nanosheet and reducibility of DHAA.The sensitivity of this method was better than those of ic-ELISA and p-ELISA.