RESUMO
The present research utilized a simplified procedure for developing a novel electro-chemical DNA biosensor based on a carbon paste electrode (CPE) modified with three-dimensional (3D) cubic Eu3+/Cu2O nanostructures with clover-like faces (Eu3+/Cu2O CLFNs). The modified electrode was applied to monitor electro-chemical interactions between dsDNA and cytarabine for the first time. Then, the decreased oxidation signal of guanine following the interactions between cytarabine and dsDNA was utilized as an indicator for selectively determining cytarabine using differential pulse voltammetry (DPV). According to the findings, the oxidation peak current of guanine was linearly proportionate with the cytarabine concentration in the range between 0.01 and 90 µM. Additionally, the limit of quantification (LOQ) and the limit of detection (LOD) respectively equaled 9.4 nM and 2.8 nM. In addition, the repeatability, applicability and reproducibility of this analysis to drug dosage forms and human serum samples were investigated. Furthermore, UV-vis spectroscopy, DPV, docking and viscosity measurements were applied to elucidate the interaction mechanism of dsDNA with cytarabine. It was found that this DNA biosensor may be utilized to sensitively, accurately and rapidly determine cytarabine.