Preparation, Characterization Of Titanium Dioxide Nanorods And Their Application As Anti-tumor Drug

Nowadays, with the fast development of nanotechnology, the research ofbio-application of nanoparticles is thereupon springing up. Nanoscale titaniumdioxide is widely produced and used in diverse fields of coating, self-cleaner,cosmetics, food additive, etc., because of its inherent physical and chemicaladvantages. However, the study on the application of titanium dioxide nanoparticlesas anti-tumor drug is still poor so far. In this paper, TiO₂nanorods （TiO₂-NRs） weresynthesized by hydrothermal method and effects on inhibiting4T1tumor of TiO₂nanorods and TiO₂nanotubes （TiO₂-NTs） were discussed. The main contents are asfollows:1) TiO₂-NRs with good morphology were prepared by treating the TiO₂nanoparticles at150℃for35h using hydrothermal reaction. The samples werecharacterized by means of X-ray diffraction （XRD）, transmission electron microscopy（TEM）, scanning electron microscope （SEM）, and infrared ray （IR）. TiO₂-NRsprepared are anatase type and their lengths were about150nm. The TiO₂-NRs alsoshow good ratio of height to diameter and are hydrophilic with many hydroxyl groupson the surface.2) BABL/C mices bearing breast cancer were used to study the anti-tumor defenceof TiO₂-NRs and TiO₂-NTs. Via mice tail vein administration，the inhibiting tumoreffects of nano TiO₂were decided. The results show both TiO₂-NRs and TiO₂-NTshave effects of inhibiting tumor grouth and the inhibitory rate of TiO₂-NRs wasobviously higher. The inhibitory rate was45.2%for doseage group of25mg/kg.3) In order to further study the tumor suppression mechanisms of TiO₂-NRs andTiO₂-NTs, we tested the levels of free radicals and immune factors in serum of tumorbearing mice. The results demonstrated that TiO₂-NRs and TiO₂-NTs had nosignificant effect on free radical level in serum, but TiO₂-NRs could significantlyenhance the level of Th1type immune factors. From the distribution measurement ofTi elements in mice and electron microscope investigation of tissues, we found there was no TiO₂-NRs and TiO₂-NTs in the tumor. Based on our results we inferred thatthe tumor inhibition of TiO₂-NRs is mainly through the immune suppression.