Antibacterial characteristics of TiO2 nano-objects and their interaction with biofilm

The antibacterial activity of as-synthesised TiO 2 nanoparticles (NPs) is determined on biofilm formed by Enterobacter sp. (1.25 mu m, Gram-negative bacteria). Nano-sized particles were characterised and their biological interaction was studied by electron microscopy images that revealed the complete entrapment of NPs into the mucilaginous polysaccharide of Enterobacter sp. leading to membrane damage at even low concentration of NPs i.e. 700 mu g mL(-1) under 72 h of incubation. At this condition, the antibacterial characteristic was observed to be the highest as confirmed by calculating the population of bacterial cell growth with respect to concentration of NPs. The mechanism of biological interaction is the formation of NPs agglomerates that are effective in 'plugging' the bacterial outermost layer and cause destruction. Our results confirm that nano-sized TiO2 particles are potent inhibitors of bacterial biofilm and thus can be utilised to treat wound infection which is otherwise challenging and is not reported till date. Antibacterial characteristics by TiO2 (anatase phase) nanoparticles of size between 40 and 100 nm were noted against the biofilm formed by Gram-negative bacteria when the concentration of nanoparticles was varied from 300 to 1300 mu g mL(-1).