title: An aptasensor for ochratoxin A based on grafting of polyethylene glycol on a boron-doped diamond microcell.
abstract: A novel strategy for the fabrication of an electrochemical label-free aptasensor for small-size molecules is proposed and demonstrated as an aptasensor for ochratoxin A (OTA). A long spacer chain of polyethylene glycol (PEG) was immobilized on a boron-doped diamond (BDD) microcell via electrochemical oxidation of its terminal amino groups. The amino-aptamer was then covalently linked to the carboxyl end of the immobilized PEG as a two-piece macromolecule, autoassembled at the BDD surface, forming a dense layer. Due to a change in conformation of the aptamer on the target analyte binding, a decrease of the electron transfer rate of the redox [Fe(CN)6](4-/3-) probe was observed. To quantify the amount of OTA, the decrease of the square wave voltammetry (SWV) peak maximum of this probe was monitored. The plot of the peak maximum against the logarithm of OTA concentration was linear along the range from 0.01 to 13.2 ng/L, with a detection limit of 0.01 ng/L. This concept was validated on spiked real samples of rice.
authors.affiliation: Laboratory of Interfaces and Advanced Materials, University of Monastir, 5019 Monastir, Tunisia; University of Lyon, Institute of Analytical Sciences, UMR CNRS 5280, 69100 Villeurbanne, France.
authors.forename: A
authors.initials: A
authors.lastname: Chrouda
authors.affiliation: University of Lyon, Institute of Analytical Sciences, UMR CNRS 5280, 69100 Villeurbanne, France.
authors.forename: A
authors.initials: A
authors.lastname: Sbartai
authors.affiliation: University of Lyon, Institute of Analytical Sciences, UMR CNRS 5280, 69100 Villeurbanne, France.
authors.forename: A
authors.initials: A
authors.lastname: Baraket
authors.affiliation: University of Lyon, Institute of Nanotechnology of Lyon, UMR CNRS 5270, 69622 Villeurbanne Cedex, France.
authors.forename: L
authors.initials: L
authors.lastname: Renaud
authors.affiliation: Laboratory of Interfaces and Advanced Materials, University of Monastir, 5019 Monastir, Tunisia.
authors.forename: A
authors.initials: A
authors.lastname: Maaref
authors.affiliation: University of Lyon, Institute of Analytical Sciences, UMR CNRS 5280, 69100 Villeurbanne, France. Electronic address: nicole.jaffrezic@univ-lyon1.fr.
authors.forename: N
authors.initials: N
authors.lastname: Jaffrezic-Renault
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis; D016607:Aflatoxin M1 / Q000032:analysis; D000465:Algorithms; D001895:Boron / Q000737:chemistry; D002138:Calibration; D002274:Carcinogens, Environmental / Q000032:analysis*; D018130:Diamond / Q000737:chemistry; D055664:Electrochemical Techniques; D004566:Electrodes; D005506:Food Contamination; D005513:Food Inspection / Q000379:methods*; D005602:France; D057230:Limit of Detection; D009793:Ochratoxins / Q000032:analysis*; D012275:Oryza / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D015203:Reproducibility of Results; D012639:Seeds / Q000737:chemistry; D013499:Surface Properties
chemical_list: D002274:Carcinogens, Environmental; D009793:Ochratoxins; C025589:ochratoxin A; D011092:Polyethylene Glycols; D016607:Aflatoxin M1; D018130:Diamond; D016604:Aflatoxin B1; C045354:ochratoxin B; D001895:Boron
keywords: Aptasensor; BDD microcell; Ochratoxin A; Polyethylene glycol; Square wave voltammetry