In the preset study, ZnO nanoparticles were synthesized by thermal treatment method and the ZnO/SiO2 and ZnO/SiO2/RGO nanocomposites were obtained by polymerization method. The degree of crystallinity, microstructure and phase composition were investigated by using different characterization techniques, i.e., X-ray diffraction, field emission scanning electron microscope, transform infrared spectroscopy and Raman spectroscopy, respectively. The compositions of the samples were determined by Energy dispersive X-ray analysis at room temperature. The surface areas of samples were obtained from nitrogen gas adsorption–desorption isotherms by Brunauer–Emmett–Teller analysis at 77 K. In addition, viability of breast tumor cells and normal 3T3-fibroblasts after exposure to RGO, of ZnO/SiO2 and ZnO/SiO2/ RGO were evaluated using MTT assay. RGO had no toxicity and almost all breast tumor cells and fibroblasts were viable after exposure to RGO. Furthermore, the toxic effect of ZnO/SiO2/RGO and of ZnO/SiO2 was more in breast tumor cells compared to normal 3T3 fibroblasts. However of ZnO/SiO2 had a mild effect compared with ZnO/SiO2/RGO.
