Development of a highly efficient DNA-based biosensor using a functionalized MoS₂/polypyrrole nanocomposite for mitomycin C determination

Abstract

In this study, plate-like Eu³⁺-doped MoS₂ nanoparticles (PL-Eu³⁺-doped MoS₂ NPs) were successfully synthesized via a simple hydrothermal method and characterized using energy-dispersive X-ray spectroscopy (EDX), field-emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD). Subsequently, a novel electrochemical DNA biosensor was developed by modifying pencil graphite electrodes (PGEs) with the synthesized nanocomposite and polypyrrole (PPy) for the sensitive detection of mitomycin C (MC). The interaction between double-stranded DNA (ds-DNA) and MC was thoroughly investigated using differential pulse voltammetry (DPV), spectrophotometry, and molecular docking methods. The decrease in the oxidation peak currents of adenine base in an acetate buffer solution (pH 4.80) was employed as a reliable indicator of the interaction event. The constructed biosensor (ds-DNA/PL-Eu³⁺-doped MoS₂/PGE) exhibited a linear response toward MC concentrations ranging from 1 to 75 μg/mL, achieving a low detection limit of 0.8 μg/mL. The sensor's performance was further validated in real sample analyses, demonstrating excellent recovery values between 97 % and 104 %, thereby confirming its potential for practical applications in biomedical and environmental monitoring. UV/Vis spectroscopic data combined with molecular docking analyses indicated substantial interaction between mitomycin and DNA, with evidence supporting groove binding as the predominant binding mode.