Effect of palladium-supported graphene oxide nanozymes with dual enzyme-like activity on apoptosis of brain glioma cells

Objective:To construct palladium-supported graphene oxide (GO@Pd) nanozymes, and to explore the effect of their enzyme-like activity on the apoptosis of brain glioma cells.Methods:GO@Pd nanozymes were synthesized and characterized by in-situ growth method.The superoxide dismutase(SOD)-like activity, peroxidase (POD)-like activity, and glutathione (GSH) consumption ability of GO@Pd were detected in vitro.The formation of hydroxyl radical(·OH^-)was detected by methylene blue.The cell counting kit-8 was used to assess the biosafety of GO@Pd in vitro.Pd, GO and GO@Pd were incubated with human brain astroglioblastoma (U-118MG)cells, respectively, and the intracellular reactive oxygen species (ROS) levels were measured by DCFH-DA fluorescent probes.Mitochondrial membrane potential was detected by mitochondrial membrane potential staining.Results:A series of material characterization showed that GO@Pd nanozymeswith uniform size and good dispersion were prepared successfully.The test results of enzyme-like activity showed that GO@Pd possessed both SOD-like and POD-like enzyme activities and could catalyze H₂O₂ to produce ·OH^-and consume GSH.The viability of C8-D1A cells was maintained above 90% when the concentration of GO@Pd was from 0 to 100 μg/mL.Compared with the blank control group, the ROS level of U-118MG cells in GO@Pd group significantly increased (P< 0.001), and the red/green fluorescence intensity ratio of mitochondrial membrane potential staining significantly decreased (P< 0.000 1).Conclusion:The GO@Pd nanozymes with dual enzyme-like activity have been successfully prepared.They can induce mitochondrial damage by promoting intracellular ROS production in glioma cells, thereby triggering apoptosis in glioma cells.