Detection of pesticide residues using an immunodevice based on negative dielectrophoresis.
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.
Ramón-Azcón
Javier
J
Applied Molecular Receptors Group, IIQAB-CSIC, Barcelona, Spain.
Kunikata
Ryouta
R
Sanchez
F-J
FJ
Marco
M-P
MP
Shiku
Hitoshi
H
Yasukawa
Tomoyuki
T
Matsue
Tomokazu
T
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
D004785:Environmental Pollutants; D010575:Pesticides; D001280:Atrazine