采用三种低温溶胶-凝胶法制备了具有不同Fe3O4掺杂量的磁靶向纳米Fe3O4-TiO2复合物,通过X射线衍射(XRD)、透射电镜(TEM)、傅里叶变换红外(FTIR)光谱、紫外-可见(UV-Vis)光谱、荧光光谱(FS)及磁性能分析等表征方法筛选出包覆均匀、分散性好、磁性能优异及光催化活性较高的纳米Fe3O4-TiO2复合物.以四甲基偶氮唑蓝(MTT)法检测肝癌细胞(HepG2)的存活率,考察纳米Fe3O4-TiO2复合物在外磁场作用下对HepG2细胞的光催化杀伤效应.结果表明:采用方法三制备的5％(质量分数)Fe3O4-TiO2复合物具备核-壳结构,在混悬液中分散性较好,平均粒径约为50 nm,具有较强的光催化活性和良好的磁响应性,同时将纳米TiO2的光响应范围拓宽至444 nm;在外磁场作用下,紫外光和可见光激发纳米Fe3O4-TiO2复合物对HepG2细胞的杀伤效应差异不大,且均强于纳米TiO2;其杀伤效应在0-1.0T范围内随着外磁场强度的增大而增强.%Fe3O4-TiO2 nanoparticles with different doped amounts of Fe3O4 were prepared by three sol-gel methods at low temperature. They were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, fluorescence spectroscopy (FS), and magnetic performance. The nanoparticles which had uniform coating, good dispersion, excellent magnetism, and high photocatalytic activity were screened. The survival rates of hepatoma carcinoma cells (HepG2) were measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) cell proliferation assay, and the photo-killing effect of screened Fe3O4-TiO2 nanoparticles on HepG2 cells was investigated in different external magnetic fields. The results indicated that the core-shell structure 5% (mass fraction) Fe3O4-TiO2 nanoparticles prepared by the third method displayed good dispersion in suspension, high photocatalytic activity, and excellent magnetic responsivity. The average particle size of the 5%Fe3O4-TiO2 particles was 50 nm. Meanwhile, the photoresponsive range of TiO2 was extended to 444 nm. In the external magnetic fields, the Fe3O4-TiO2 nanoparticles excited either by ultraviolet or visible light showed no obvious difference on killing effect, while in both cases had a higher killing effect than that of nano-TiO2. Furthermore, the killing effect was enhanced with the increased magnetic field strength in the range of 0-1.0 T.
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