title: Enzyme-controlled dissolution of MnO2nanoflakes with enzyme cascade amplification for colorimetric immunoassay.
abstract: A new colorimetric immunosensing platform accompanying enzyme cascade amplification strategy was fabricated for quantitative screening of small-molecular mycotoxins (aflatoxin B1, AFB1used in this case) coupling with enzyme-controlled dissolution of MnO2nanoflakes. The visual colored assay was executed by high-efficient MnO2-3,3',5,5'-tetramethylbenzidine (TMB) system (blue). In the presence of ascorbic acid, MnO2nanoflakes were dissolved into Mn2+ions, thus resulting in a perceptible color change from blue to colorless. The reaction could be weakened through ascorbate oxidase to catalyze ascorbic acid into dehydroascorbic acid, which indirectly depended on the concentration of ascorbate oxidase. By using ascorbate oxidase/ anti-AFB1antibody-labeled gold nanoparticles, a novel competitive-type colorimetric enzyme immunoassay was developed for detection of AFB1on AFB1-bovine serum albumin (BSA)-conjugated magnetic beads. Upon addition of target AFB1, the analyte competed with the conjugated AFB1-BSA on the magnetic beads for the labeled anti-AFB1antibody on the gold nanoparticles. Under optimal conditions, the absorbance decreased with increasing target AFB1within the dynamic range of 0.05-150ngmL-1with a detection limit of 6.5pgmL-1at the 3Sblanklevel. The precision and specificity of the MnO2-TMB-based immunosensing system were acceptable. In addition, method accuracy was further validated for monitoring spiked peanut samples, giving results matched well with those obtained from commercialized AFB1ELISA kit.
authors.affiliation: State Key Laboratory of Photocatalysis on Energy and Environment, Key Laboratory of Analysis and Detection for Food Safety (Fujian Province & MOE), Institute of Nanomedicine and Nanobiosensing, Department of Chemistry, Fuzhou University, Fuzhou 350108, PR China.
authors.forename: Wenqiang
authors.initials: W
authors.lastname: Lai
authors.affiliation: State Key Laboratory of Photocatalysis on Energy and Environment, Key Laboratory of Analysis and Detection for Food Safety (Fujian Province & MOE), Institute of Nanomedicine and Nanobiosensing, Department of Chemistry, Fuzhou University, Fuzhou 350108, PR China. Electronic address: dianping.tang@fzu.edu.cn.
authors.forename: Qiaohua
authors.initials: Q
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Photocatalysis on Energy and Environment, Key Laboratory of Analysis and Detection for Food Safety (Fujian Province & MOE), Institute of Nanomedicine and Nanobiosensing, Department of Chemistry, Fuzhou University, Fuzhou 350108, PR China.
authors.forename: Mingdi
authors.initials: M
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Photocatalysis on Energy and Environment, Key Laboratory of Analysis and Detection for Food Safety (Fujian Province & MOE), Institute of Nanomedicine and Nanobiosensing, Department of Chemistry, Fuzhou University, Fuzhou 350108, PR China.
authors.forename: Junyang
authors.initials: J
authors.lastname: Zhuang
authors.affiliation: State Key Laboratory of Photocatalysis on Energy and Environment, Key Laboratory of Analysis and Detection for Food Safety (Fujian Province & MOE), Institute of Nanomedicine and Nanobiosensing, Department of Chemistry, Fuzhou University, Fuzhou 350108, PR China. Electronic address: dianping.tang@fzu.edu.cn.
authors.forename: Dianping
authors.initials: D
authors.lastname: Tang
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis*; D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry; D010367:Arachis / Q000737:chemistry / Q000382:microbiology*; D001204:Ascorbate Oxidase / Q000737:chemistry; D001231:Aspergillus flavus / Q000737:chemistry; D001560:Benzidines / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D003124:Colorimetry / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006046:Gold / Q000737:chemistry; D007118:Immunoassay / Q000379:methods; D057230:Limit of Detection; D017895:Manganese Compounds / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D010087:Oxides / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012995:Solubility
chemical_list: D055910:Antibodies, Immobilized; D001560:Benzidines; D017895:Manganese Compounds; D010087:Oxides; D012710:Serum Albumin, Bovine; C021758:3,3',5,5'-tetramethylbenzidine; D006046:Gold; D016604:Aflatoxin B1; D001204:Ascorbate Oxidase; C016552:manganese dioxide
keywords: Aflatoxin B(1); Colorimetric immunoassay; Enzyme cascade amplification; MnO(2) nanoflakes