title: Label Free QCM Immunobiosensor for AFB1 Detection Using Monoclonal IgA Antibody as Recognition Element.
abstract: This study introduces the use of an IgA isotype aflatoxin (AF) specific monoclonal antibody for the development of a highly sensitive Quartz Crystal Microbalance (QCM) immunobiosensor for the detection of AF in inhibitory immunoassay format. The higher molecular weight of IgA antibodies proved an advantage over commonly used IgG antibodies in label free immunobiosensor measurements. IgA and IgG antibodies with similar affinity for AF were used in the comparative studies. Sensor surface was prepared by covalent immobilization of AFB1, using self assembled monolayer (SAM) formed on gold coated Quartz Crystal, with 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxy succinimide (EDC/NHS) method using a diamine linker. Nonspecific binding to the surface was decreased by minimizing the duration of EDC/NHS activation. Sensor surface was chemically blocked after AF immobilization without any need for protein blocking. This protein free sensor chip endured harsh solutions with strong ionic detergent at high pH, which is required for the regeneration of the high affinity antibody-antigen interaction. According to the obtained results, the detection range with IgA antibodies was higher than IgG antibodies in QCM immunosensor developed for AFB1.
authors.affiliation: TÜBİTAK, The Scientific and Technological Research Council of Turkey, Marmara Research Center, Genetic Engineering and Biotechnology Institute, Gebze, 41470 Kocaeli, Turkey. ozlem.ertekin@tubitak.gov.tr.|Department of Molecular Biology and Genetics, Gebze Technical University, 41400 Kocaeli, Turkey. ozlem.ertekin@tubitak.gov.tr.
authors.forename: Özlem
authors.initials: Ö
authors.lastname: Ertekin
authors.affiliation: TÜBİTAK, The Scientific and Technological Research Council of Turkey, Marmara Research Center, Genetic Engineering and Biotechnology Institute, Gebze, 41470 Kocaeli, Turkey. selma.ozturk@tubitak.gov.tr.
authors.forename: Selma
authors.initials: S
authors.lastname: Öztürk
authors.affiliation: Department of Physics, Gebze Technical University, 41400 Kocaeli, Turkey. zozturk@gtu.edu.tr.
authors.forename: Zafer Ziya
authors.initials: ZZ
authors.lastname: Öztürk
mesh_terms: D016604:Aflatoxin B1 / Q000276:immunology / Q000302:isolation & purification*; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods*; D006046:Gold; D006801:Humans; D007070:Immunoglobulin A / Q000737:chemistry* / Q000276:immunology; D058525:Quartz Crystal Microbalance Techniques
chemical_list: D000911:Antibodies, Monoclonal; D007070:Immunoglobulin A; D006046:Gold; D016604:Aflatoxin B1
keywords: IgA monoclonal antibody; QCM immunosensor; aflatoxin immobilization; chemical blocking