Effectivity of Titanium Oxide Based Nano Particles on E. coli from Clinical Samples

Nanoparticles composed of Titanium Oxide (TiO₂) are non toxic, durable, stable and have a high refractive index with a lot of scope in biomedical applications. Due to their antibacterial effects, they can be applied to inanimate objects like glass, metal and even biomedical implants.

This study was conducted to assess the antibacterial effect of Titanium Oxide (TiO₂) alone or with Silver (Ag) as an additive on Escherichia coli.

Escherichia coli isolates (n=25) sensitive to most of the drugs including first generation cephalosporins, ampicillin and amoxycillin from various samples like pus, urine, sputum and blood were placed onto the glass slides containing TiO₂ annealed at 200°C, 400°C, TiO₂ with 0.1% Ag as additive, TiO₂ with 0.3% Ag, and TiO₂ with 0.6% Ag as additive. Samples from this were inoculated at every hour onto sterile petri plates and observed for growth after overnight incubation at 37°C.

The organisms which were inoculated onto TiO₂ annealed at 200°C showed a slower reduction rate from >1 × 108 cfu/ml to <1 × 10 cfu/ml only after six hours of incubation in visible light. Complete absence of colony forming units was observed after eight hours of incubation. The samples treated with TiO₂ at 400°C showed no growth after six hours of incubation itself. Samples treated with TiO₂ with increasing gradations of silver as additives showed proportional reduction in the incubation time for the complete absence of colony forming units.

Our study shows that pure titanium oxide has a high antibacterial effect on pathogenic samples of Escherichia coli from clinical isolates, which is further increased with the addition of increasing concentrations of silver.