Fig. 2

Study the antibacterial activity and bio-safety dosage of DE-ZnO. A Antibacterial efficiency of DE-No against Gram-negative bacteria (E. coli, S. enterica) at a concentration of 10 µg/mL. B SEM image showing the surface of DE-ZnO composites after meeting/absorbing pathogen. C Cell viability study of the cytotoxicity of DE-ZnO at different modification ratios with dosage of 0.25 mg in one hole through Cell counting Kit 8 method. D Dosage depended cytotoxicity study of DE-ZnO (ZnO: DE = 2:1, 10.61% of ZnO), L929 cells were exposed to different doses (0.5–3.0 mg) for 24 h. Each data value is mean ± SE of three independent experiments. E Schematic illustration of the Reactive oxygen species (ROS) detection, due to the band gap of semiconductor could absorb energy and release ROS which would transfer the DCFH-DA to DCF (Fluorescence); inside the SEM image of DE-ZnO confirmed that the well-wash DE-ZnO composites is without dispersed ZnO-S (blank in red cycle); meanwhile the special multi-pore morphology of ZnO-S has been marked. F Cellular ROS detection assay using DE-ZnO with different ratios of ZnO modification (ZnO:DE = 0.25:1, 0.5:1, 1:1, 2:1, 3:1, and 4:1). G Non-cellular ROS detection assay using DE-ZnO with different ratios of ZnO modification (ZnO:DE = 0.25:1, 0.5:1, 1:1, 2:1, 3:1, and 4:1). H, I The mechanisms of the delay ions/ROS ‘quenching’ related antifungal property of DE-ZnO. H Non-cellular ROS detection assay using ZnO and DE-ZnO with different concentrations of nanomaterials, showing the relatedness between the pure ZnO and DE-ZnO. I Time-depended study of the effect from ROS protection, explaining the ‘quenching’. DCF, 2′,7′-Dichlorofluorescein; DCFH-DA, 2′,7′-Dichlorofluorescin diacetate, Error bars indicate the standard error of the mean based on at least three independent experiments)