title: Detection of pesticide residues using an immunodevice based on negative dielectrophoresis.
abstract: The detection of atrazine using a novel optical immunosensing technique based on negative dielectrophoresis (n-DEP) in microfluidic channels is described. Atrazine is a toxic triazine herbicide within the most frequently used. Polystyrene microparticles (6 microm diameters) modified with bovine serum albumin conjugated with atrazine (atrazine-BSA) were manipulated and captured when subjected to intense n-DEP electric fields. Specifically, particles were trapped when AC voltages with amplitudes of 10 V(peak) and frequencies over 1 MHz were applied to the electrodes. The immunological reaction occurring on the particles for detecting atrazine is based on an indirect competitive assay using a secondary anti-mouse immunogloburin G (IgG) antibody labeled with fluorescein isothiocyanate. The microfluidic device, with three-dimensional microelectrodes, was fabricated comprising two caged areas, allowing two simultaneous measurements inside the same microfluidic channel. The performance of this n-DEP immunosensing technique was evaluated using wine samples. The immunodevice showed a limit of detection for atrazine in buffer samples of 0.11 microgL(-1) and in pre-treated wine samples of 6.8 microg L(-1); these detection limits are lower than the maximum residue level (MRL) established by the European Community for residues of this herbicide in wine (50 microg L(-1)). This methodology offers great promise for rapid, simple, cost effective, and on-site analysis of biological, foods and beverages, and environmental samples.
authors.affiliation: Applied Molecular Receptors Group, IIQAB-CSIC, Barcelona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Ramón-Azcón
authors.forename: Ryouta
authors.initials: R
authors.lastname: Kunikata
authors.forename: F-J
authors.initials: FJ
authors.lastname: Sanchez
authors.forename: M-P
authors.initials: MP
authors.lastname: Marco
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shiku
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yasukawa
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Matsue
mesh_terms: D001280:Atrazine / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004586:Electrophoresis / Q000295:instrumentation* / Q000379:methods; D004784:Environmental Monitoring / Q000295:instrumentation* / Q000379:methods; D004785:Environmental Pollutants / Q000032:analysis*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D010575:Pesticides / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D004785:Environmental Pollutants; D010575:Pesticides; D001280:Atrazine