title: An ultrasensitive electrochemiluminescent immunoassay for aflatoxin M1 in milk, based on extraction by magnetic graphene and detection by antibody-labeled CdTe quantumn dots-carbon nanotubes nanocomposite.
abstract: An ultrasensitive electrochemiluminescent immunoassay (ECLIA) for aflatoxins M1 (ATM1) in milk using magnetic Fe3O4-graphene oxides (Fe-GO) as the absorbent and antibody-labeled cadmium telluride quantum dots (CdTe QDs) as the signal tag is presented. Firstly, Fe3O4 nanoparticles were immobilized on GO to fabricate the magnetic nanocomposites, which were used as absorbent to ATM1. Secondly, aflatoxin M1 antibody (primary antibody, ATM1 Ab1), was attached to the surface of the CdTe QDs-carbon nanotubes nanocomposite to form the signal tag (ATM1 Ab1/CdTe-CNT). The above materials were characterized. The optimal experimental conditions were obtained. Thirdly, Fe-GO was employed for extraction of ATM1 in milk. Results indicated that it can adsorb ATM1 efficiently and selectively within a large extent of pH from 3.0 to 8.0. Adsorption processes reached 95% of the equilibrium within 10 min. Lastly, the ATM1 with a serial of concentrations absorbed on Fe-GO was conjugated with ATM1 Ab1/CdTe-CNT signal tag based on sandwich immunoassay. The immunocomplex can emit a strong ECL signal whose intensity depended linearly on the logarithm of ATM1 concentration from 1.0 to 1.0 × 10(5) pg/mL, with the detection limit (LOD) of 0.3 pg/mL (S/N = 3). The method was more sensitive for ATM1 detection compared to the ELISA method. Finally, ten samples of milk were tested based on the immunoassay. The method is fast and requires very little sample preparation, which was suitable for high-throughput screening of mycotoxins in food.
authors.affiliation: The State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo, China. ganning@nbu.edu.cn
authors.forename: Ning
authors.initials: N
authors.lastname: Gan
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.forename: Ping
authors.initials: P
authors.lastname: Xiong
authors.forename: Futao
authors.initials: F
authors.lastname: Hu
authors.forename: Yuting
authors.initials: Y
authors.lastname: Cao
authors.forename: Tianhua
authors.initials: T
authors.lastname: Li
authors.forename: Qianli
authors.initials: Q
authors.lastname: Jiang
mesh_terms: D016607:Aflatoxin M1 / Q000032:analysis* / Q000276:immunology; D000818:Animals; D000906:Antibodies / Q000737:chemistry* / Q000276:immunology; D019187:Cadmium Compounds / Q000737:chemistry; D004563:Electrochemistry; D005506:Food Contamination / Q000032:analysis; D006108:Graphite / Q000737:chemistry; D007118:Immunoassay / Q000379:methods; D008163:Luminescent Measurements; D058185:Magnetite Nanoparticles / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D008892:Milk / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000737:chemistry; D045663:Quantum Dots; D013691:Tellurium / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000906:Antibodies; D019187:Cadmium Compounds; D058185:Magnetite Nanoparticles; D037742:Nanotubes, Carbon; D016607:Aflatoxin M1; D006108:Graphite; D013691:Tellurium; C028337:cadmium telluride