Electrochemical Monitoring of Biointeraction Between Glyphosate and DNA By Using Disposable Pencil Graphite Electrodes

Abstract

Glyphosate (GLY) is a worldwide known chemical used to control non-specific vegetation. It is evaluated as “probably carcinogenic to humans” by The International Agency for Research on Cancer. Its cytotoxic effects was investigated on tropical frog larvae, mouse oocytes, plants, humans and animals and it was reported that GLY causes DNA double strand-breaks. Therefore, the use of GLY containing pesticides is controversial in many countries. Herein, biointeraction between GLY and double stranded DNA (dsDNA) was performed and this biointeraction was monitored by using disposable pencil graphite electrodes (PGEs). In this study, as the first step, dsDNA was immobilized at the surface of PGEs, then, the biointeraction was done in the presence of GLY. Electrochemical monitoring of the biointeraction was performed using differential pulse voltammetry (DPV) technique. The oxidation signal of guanine base was monitored at +1.0V and the changes at the guanine signal were evaluated in terms of the biointeraction process. Electrochemical monitoring of the biointeraction between dsDNA and GLY containing pesticide was also studied. The biointeraction was investigated using 25-150 µg/mL GLY or 5-25 µg/mL GLY contained pesticide during different exposure time varying from 5 to 30 min. The most decrease at the guanine signal was obtained in the presence of 100 µg/mL GLY or 15 µg/mL GLY contained pesticide during 5 min interaction. The results suggested that GLY caused DNA damage and GLY contained pesticide had more adverse effect on dsDNA structure. These results were in parallel to the results obtained by animal experiments or single cell gel electrophoresis (SGCE) assay. This is the first study in the literature for the electrochemical investigation of dsDNA and GLY interaction by using disposable PGEs.