In vitro Cytotoxic Studies of Ultrafine TiO_2/Graphene Oxide Sheet Nanocomposites in Human Alveolar Epithelial Cells

摘要

The novel TiO_2/graphene sheet (TiO_2/GSs) nanocomposites were synthesized using graphene oxide sheets and TiCl_3. All target composites were characterized by transmission electron microscopy (TEM), X-ray electron diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectra (EDX), and the surface areas were tested with the Brunauer-Emmett-Teller (BET) method. We studied the cytotoxicity of TiO_2/GSs nanoparticles on A549 cells by examining the influence of TiO_2/GSs on cell morphology and viability by methyl thiazolyl tetrazolium (MTT) assay. We also determined membrane integrity and apoptosis of A549 cells after different doses of TiCVGSs exposure by LDH assay and flow cytometry. Assay of A549 cell viability showed regular reductions with a time- and dose-dependent tendency after exposure to pure TiO_2, TiO_2/4.2wt% GSs and TiO_2/6wt% GSs for 24 hrs or 48 hrs. The LDH released and cellular apoptosis also had a dose-dependent effect, which was associated with the surface area of TiO_2/4.2wt% GSs. Our results provide essential knowledge of the acceptable biocompatibility of TiCVGSs nanocomposites, and only when cells were exposed at a high concentration (≥50 μg/mL), and for a prolonged period of time did TiO2/GSs nanoparticles exhibit minimal cytotoxicity against A549 cells.