A novel smartphone-based electrochemical cell sensor for evaluating the toxicity of heavy metal ions Cd2+, Hg2+, and Pb2+ in rice

A novel smartphone-based electrochemical cell sensor was developed to evaluate the toxicity of heavy metal ions, such as cadmium (Cd2+), lead (Pb2+), and mercury (Hg2+) ions on Hep G2 cells. The cell sensor was fabricated with reduced graphene oxide (RGO)/molybdenum sulfide (MoS2) composites to greatly improve the biological adaptability and amplify the electrochemical signals. Differential pulse voltammetry (DPV) was employed to measure the electrical signals induced by the toxicity of heavy metal ions. The results showed that Cd2+, Hg2+, and Pb2+ significantly reduced the viability of Hep G2 cells in a dose-dependent manner. The IC50 values obtained by this method were 49.83, 36.94, and 733.90 mu M, respectively. A synergistic effect was observed between Cd2+ and Pb2+ and between Hg2+ and Pb2+, and an antagonistic effect was observed between Cd2+ and Hg2+, and an antagonistic effect at low doses and an additive effect at high doses were found in the ternary mixtures of Cd2+, Hg2+, and Pb2+. These electrochemical results were confirmed via MTT assay, SEM and TEM observation, and flow cytometry. Therefore, this new electrochemical cell sensor provided a more convenient, sensitive, and flexible toxicity assessment strategy than traditional cytotoxicity assessment methods.

Automated summary

A novel smartphone-based electrochemical cell sensor was developed to evaluate the toxicity of heavy metal ions on Hep G2 cells. The sensor utilized RGO/MoS2 composites to improve adaptability and amplify signals, showing dose-dependent reductions in cell viability by Cd2+, Hg2+, and Pb2+. Synergistic effects were observed between Cd2+ and Pb2+ and between Hg2+ and Pb2+, while antagonistic effects were found between Cd2+ and Hg2+, and in ternary mixtures of Cd2+, Hg2+, and Pb2+. The new sensor provided a more convenient and sensitive toxicity assessment strategy compared to traditional methods.