Titanium dioxide nanoparticles as antibacterial agents against some pathogenic bacteria
Lubna Abdulazeem*, BahaHamdi Hakim AL-Amiedi, Hadeel Alana Alrubaei, Yasir H. AL-Mawlah

Background: Today, many of studies have been done to investigate the efficacy of antimicrobial nanoparticles (NPs) against the pathogens as drug resistance bacteria and metal NPs have been reported with antimicrobial properties. Materials and Methods: In the present study, titanium dioxide (TiO2) NPs with 35 nm size were characterized by X-ray diffraction and Fourier transform infrared then investigates their antibacterial activity, antibiofilm formation, and invasion against various pathogenic bacteria from Gram-positive Streptococcus pyogenes and Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Proteus vulgaris, and Serratia marcescens. Antimicrobial activity of TiO2 NPs was examined by disk diffusion assay using dilutions of 500, 250, 125, 62.5, and 31.25 ?g/ml also the minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each isolate is determined. Results: TiO2 NPs show powerful broad-spectrum antibacterial activity against tested bacteria with increase in inhibition zone diameter that is directly proportional with the increase in NP concentration that even exceeded the activity of selected antibiotics. The MIC of TiO2 NPs ranged from 125 ?g/ml to 31.25 ?g/ml and the MBC ranged from 125 ?g/ml to 500 ?g/ml. The metal NPs highly inhibited bacterial biofilm growth and invasion, other studies show that TiO2 NPs strongly attached to the bacterial cells that contributed to their inhibitory effect on bacterial biofilm growth formation and invasion. We showed that bacterial biofilm growth was reduced at MIC concentrations of TiO2 NPs compared with another test without the NPs. Conclusion: NPs with a suitable concentration are reduced the biofilm growth significantly. It is highly recommended using TiO2 NPs as an economic alternative antibacterial and antibiofilm agent, especially in treating ectopic infections without taking the risk of developing resistant bacterial strains as with antibiotics.
KEY WORDS: Antibacterial activity, Biofilm, Nanoparticles, Titanium dioxide