Biosensor based on ds-DNA decorated chitosan modified multiwall carbon nanotubes for voltammetric biodetection of herbicide amitrole

• Published in: Colloids and surfaces, B, Biointerfaces Vol. 109; pp. 45 - 51
• Main Authors: Ensafi, Ali A., Amini, Maryam, Rezaei, Behzad
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2013
• Subjects: absorption; Amitrole; Amitrole - analysis; Animals; Biosensing Techniques; biosensors; carbon nanotubes; chitosan; Chitosan - chemistry; Chitosan-modified multiwall carbon nanotubes; colloids; detection limit; DNA - chemistry; DNA biosensor; electrochemistry; Electrodes; graphene; Graphite - chemistry; Herbicides - analysis; Intercalative binding; Male; Nanotubes, Carbon - chemistry; oxidation; Salmon; spermatozoa; Spermatozoa - chemistry; Voltammetry; Voltammetry; Intercalative binding; Chitosan-modified multiwall carbon nanotubes; Amitrole; DNA biosensor
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2013.03.031

We introduceda DNA biosensor for determination of amitrole using differential pulse voltammetry. We immobilized a mixture of MWCNTs and chitosan on the surface of pretreated pencil graphite electrode for improving the immobilization of the ds-DNA on the surface. We used the signal of amitrole, after interaction with the ds-DNA, for construction of a calibration curve and ultimately quantitative inspections. Amitrole could be detected as low as 0.017ngmL−1. •An electrode modified with chitosan decorated with a ds-DNA was prepared.•The interaction of amitrole with salmon sperm DNA was studied at the electrode.•The peak current of the modified electrode is proportional to amitrole.•Amitrole could be detecting as low as 0.017ngmL−1. The interaction of amitrole and salmon sperm ds-DNA was studied using UV–vis and differential pulse voltammetry (DPV) at both bare and DNA-modified electrodes. Amitrole showed an oxidation peak at 0.445V at a bare pencil graphite electrode (PGE). When ds-DNA was added into the amitrole solution, the peak current of amitrole decreased and the peak potential underwent a shift. UV–vis spectra showed that the absorption intensity of the ds-DNA at 260nm decreased with increasing amitrole concentration, proving the interaction between amitrole and the ds-DNA. The results also showed that amitrole could interact with the ds-DNA molecules via the intercalative binding mode. Finally, a pretreated pencil graphite electrode (PGE) modified with multiwall carbon nanotubes (MWCNTs) and chitosan (CHIT) decorated with the ds-DNA were tested in order to determine amitrole content in solution. Electrochemical oxidation of amitrole bonded on DNA/MWCNTs–CHIT/PGE was used to obtain an analytical signal. A linear dependence was observed to exist between the peak current and 0.025–2.4ngmL−1 amitrole with a detection limit of 0.017ngmL−1. The sensor showed a good selectivity and precision for the determination of amitrole. Finally, applicability of the biosensor was evaluated by measuring the analyte in soil and water samples with good selectivity.