Voltammetric behavior of benznidazole at a DNA-electrochemical biosensor

Abstract

Benznidazole is a drug used commonly as a therapeutic agent against Chagas' disease in Brazil. To clarify the cytotoxic action of benznidazole the electrochemical reduction of benznidazole has been investigated using a DNA-electrochemical biosensor, prepared by modification of a glassy carbon electrode with DNA, and the results compared with reduction at a bare glassy carbon electrode. The dependence of peak potential with pH follows slopes of 59 and 52 mV per pH unit in acid media, respectively, which corresponds to a mechanism involving the same number of electrons and protons. In neutral and alkaline solution no significant dependence of peak potential with pH was found. During the electrochemical reduction of benznidazole the formation of the hydroxylamine derivative occurs, involving a total of four electrons. The potentials for reduction were less negative when using the DNA-modified glassy carbon electrode than at the bare glassy carbon electrode although the mechanism was the same, and at pH 7.51 the peak current was four times higher than that obtained with the bare electrode. The DNA-biosensor enabled pre-concentration of the drug onto the electrode surface and the in situ damage caused to the DNA on the electrode surface by the product of benznidazole reduction could be detected electrochemically. The results are in agreement with the hypothesis that the hydroxylamine derivative is the reactive species responsible for the cytotoxic action of benznidazole.

Voltammetric and spectroscopic studies on the interaction of tilmicosin with bovine serum albumin at different pHs

“…The interactions between drug molecules and bioactive molecules, such as DNA, proteins and amino acids have aroused great interest in recent years [3][4][5][6][7][8]. Bovine serum albumin (BSA) has been one of the most extensively studied proteins [9].…”

Electrochemical Biosensors for Drug Analysis

“…may displace them from the transducer surface. As recent examples, ssDNA or dsDNA were physically adsorbed onto the surface of various carbon-based electrodes such as GCE, CPE, SPCE, and PGE for DNA-drug interaction studies [15][16][17][18]. The random immobilization of biomolecules, however, which occurs during physisorption cannot be regarded as optimal for efficient interaction studies.…”

Nucleic acid sensor for insecticide detection

“…Lucarelli et al (2002) developed an electrochemical biosensor based on screen-printed carbon electrode for monitoring of toxicants/pollutants like bisphenol (1.0-5.0 mg/mL), o-chlorophenol (OCP), and 2-aminoanthracene (2-AA) (0.08-20 mg/mL) using square wave voltammetry (SWV) technique. DNA immobilized glassy carbon electrodes have been used to investigate the interaction of benznidazole with DNA molecule (La-Scalea et al, 2002). The dsCT-DNA physisorbed onto polypyrrole (PPy)-polyvinyl sulfonate (PVS) film has been used to detect 2-AA (0.01-20 ppm) and OCP (0.1-30 ppm) using cyclic voltammetry (Arora et al, 2006).…”