Highly sensitive biosensor for detection of DNA nucleobases: Enhanced electrochemical sensing based on polyaniline/single-layer MoS2 nanosheets nanocomposite modified carbon paste electrode

Robust detection of DNA as a molecule that encodes genetic instructions is getting significant attention in recent years due to its promising applications in diseases diagnosis and treatment, forensic analysis, food safety evaluation, environmental monitoring, and so on. In this research, a simple, rapid and multiplex electrochemical method based on single-layer molybdenum disulfide (MoS2) nanosheets sensing platform and differential pulse voltammetry (DPV) method for detection of DNA nucleobases (DNANBs) was set up without any pretreatment or separation process. Hence, the carbon paste electrode modified with MoS2 (MoS2/CPE) was selected, and the effects of different parameters such as supporting electrolyte composition and pH were optimized to obtain the best peak potential separation and high sensitivity. Then, the individual, respective and simultaneous determinations of DNANBs were performed by controlling the certain experimental conditions. The results exhibited the excellent sensitivity, low limit of detection, and high selectivity of the electrochemical biosensor. Moreover, the peak current values were linearly dependent on the concentration of DNANBs. For comparison, common methods for determination of DNANBs were analyzed based on the absorption of ultraviolet light and Raman spectroscopy. Finally, the proposed electrode was modified with polyaniline (PANI-MoS2/CPE) as a new biosensor for the determination of DNANBs, exhibiting good reproducibility and stability.