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The in vitro cell response was investigated on flat Ti surface vs nanostructured TiO2 nanotube surface. The titanium dioxide nanotube layers were prepared by electrochemical anodization of Ti in ethylene glycol, 5 wt% NH4F and 1ml H2O2. The nanotube layered structure and morphology were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The diameter and the length of the nanotubes are found to increase with anodization voltage. Hs27 and breast cancer cell line MCF-7 were used for cell interaction studies. Different surfaces of titanium show variation in term of growth and viability of cells. Different cell type also show different cellular responses to these surfaces. Titanium nanotube with tube diameter 90 nm promoted normal cell adherence and spreading but killed the cancer cells. The detail of the observation is discussed thoroughly in this paper.

Bacterial are highly transmitted in our environment and have been identified as a primary contributor to the problem of indoor air quality and consequently lead to the illness of the occupants. Recently, nanotechnology represents an innovative approach to develop new formulations based on metallic nanoparticles with antimicrobial properties. TiO2 has great promise to diminish bacterial activity. Antimicrobial activity of TiO2and Ag-TiO2 nanoparticles against Escherichia coli was examined in this study. TiO2 nanoparticles with various silver contents were synthesized by sol gel method to produce uniform size, unagglomerated state and homogeneous nanoparticles. The nanoparticles were characterized by X-Ray diffraction (XRD) and transmittance electron microscopy (TEM). The effects of different silver concentration were studied using cotton diffusion test under fluorescence light irradiation. 0.06 mol % Ag-TiO2 revealed best antibacterial activity. 0.06 mol % Ag-TiO2 have antibacterial inhibition zone of 38 mm at the concentration of 2.0 M against E. coli. Swab test bacterial counts on left palm, tile, mouse pad and cotton have been tested before and after spraying with 0.06 mol % Ag-TiO2. It showed that the bacterial count decreased for entire samples. The significant enhancement in the antibacterial properties of Ag-TiO2 nanoparticles under visiblelight irradiation is related to the effect of noble metal Ag by acting as electron traps in TiO2 band gap. The phase structure, crystallite size and crystallinity of TiO2 also play an important role inantibacterial activity. The killing mechanism of Ag-TiO2 undervisible light irradiation antibacterial activity over Ag-TiO2nanoparticles was proposed based on our observations.

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