title: Silver Nanolabels-Assisted Ion-Exchange Reaction with CdTe Quantum Dots Mediated Exciton Trapping for Signal-On Photoelectrochemical Immunoassay of Mycotoxins.
abstract: Mycotoxins, highly toxic secondary metabolites produced by many invading species of filamentous fungi, contaminate different agricultural commodities under favorable temperature and humidity conditions. Herein, we successfully devised a novel signal-on photoelectrochemical immunosensing platform for the quantitative monitoring of mycotoxins (aflatoxin B1, AFB1, used as a model) in foodstuffs on the basis of silver nanolabels-assisted ion-exchange reaction with CdTe quantum dots (QDs) mediated hole-trapping. Initially, a competitive-type immunoreaction was carried out on a high-binding microplate by using silver nanoparticle (AgNP)-labeled AFB1-bovine serum albumin (AFB1-BSA) conjugates as the tags. Then, the carried AgNPs with AFB1-BSA were dissolved by acid to release numerous silver ions, which could induce ion-exchange reaction with the CdTe QDs immobilized on the electrode, thus resulting in formation of surface exciton trapping. Relative to pure CdTe QDs, the formed exciton trapping decreased the photocurrent of the modified electrode. In contrast, the detectable photocurrent increased with the increase of target AFB1 in a dynamic working range from 10 pg mL(-1) to 15 ng mL(-1) at a low limit of detection (LOD) of 3.0 pg mL(-1) under optimal conditions. In addition, the as-prepared photoelectrochemical immunosensing platform also displayed high specificity, good reproducibility, and acceptable method accuracy for detecting naturally contaminated/spiked blank peanut samples with consistent results obtained from the referenced enzyme-linked immunosorbent assay (ELISA) method.
authors.affiliation: Key Laboratory of Analysis and Detection for Food Safety (MOE & Fujian Province), Department of Chemistry, Fuzhou University , Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Youxiu
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Key Laboratory of Analysis and Detection for Food Safety (MOE & Fujian Province), Department of Chemistry, Fuzhou University , Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Analysis and Detection for Food Safety (MOE & Fujian Province), Department of Chemistry, Fuzhou University , Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Dianping
authors.initials: D
authors.lastname: Tang
authors.affiliation: Chair for Analytical Chemistry, Institute of Hydrochemistry, Technische Universität München , Marchioninistrasse 17, D-81377 München, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner
authors.affiliation: Key Laboratory of Analysis and Detection for Food Safety (MOE & Fujian Province), Department of Chemistry, Fuzhou University , Fuzhou, Fujian 350108, People's Republic of China.
authors.forename: Huanghao
authors.initials: H
authors.lastname: Yang
authors.affiliation: Chair for Analytical Chemistry, Institute of Hydrochemistry, Technische Universität München , Marchioninistrasse 17, D-81377 München, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Knopp
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis; D000818:Animals; D019187:Cadmium Compounds / Q000737:chemistry; D002417:Cattle; D055664:Electrochemical Techniques; D004566:Electrodes; D007118:Immunoassay; D008027:Light; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D009183:Mycotoxins / Q000032:analysis*; D045663:Quantum Dots / Q000737:chemistry*; D012709:Serum Albumin / Q000032:analysis; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013691:Tellurium / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D009183:Mycotoxins; D012709:Serum Albumin; C052669:aflatoxin B1-bovine serum albumin; D012710:Serum Albumin, Bovine; D012834:Silver; D016604:Aflatoxin B1; D013691:Tellurium; C028337:cadmium telluride