Cytotoxicity assessment using label-free impedimetric biosensing: Comparative evaluation with conventional assays

To address the global need for quantitative and sensitive methods to monitor the effects of chemical stress, we introduce a rapid, non-destructive impedimetric biosensor that uses in vitro cell-based systems as the biorecognition element and diazinon, an organophosphorus pesticide, as the model chemical for assessing stress. The study aimed to evaluate the biosensor's sensitivity and effectiveness relative to established in vitro cytotoxicity assays. Light microscopy confirmed cell density and viability on the electrodes, while electrochemical impedance spectroscopy (EIS) revealed a linear, concentration-dependent decrease in impedance following diazinon exposure. Crucially, the EIS biosensor demonstrated significantly lower effective concentrations (EC 50 = 0.079 mM, EC 20 = 0.012 mM, EC 10 = 0.006 mM) than in conventional assays, which proves that our biosensor detects an earlier toxicological event. We conclude that the cell-based impedimetric biosensor provides a label-free platform for non-destructive assessment of the effects of aquatic contaminants.