(397w) Antibacterial Studies On Titania Polyurethane Nanocomposite Coatings

While temporarily disinfection of a surface is possible with the help of strong cleaners, tremendous interest exists for the control of microorganisms on surfaces by effective, durable antimicrobial coatings to prevent multidrug resistant pathogens. There is a wide spectrum of potential applications for antibacterial coatings, spanning from industrial surface coatings to biomedical applications, where sterile conditions are crucial. This work examined the synthesis of nanotitanium dioxide/polyurethane (nTiO₂/PU) composite coatings prepared by using various bifunctional monomers. The antibacterial behavior of virgin PU, nTiO₂/PU and silver doped nTiO₂/PU composites were investigated qualitatively and quantitatively against both gram-negative (Escherichia coli) and gram-positive (Micrococcus luteus) bacteria. The effect of exposure time was investigated using a UV lamp and solar simulator by monitoring the growth of bacterial populations in the presence and absence of the above-mentioned nanocomposites. The distribution of nTiO₂ in the polymer matrix was enhanced by monomer functionalization in which nTiO₂ was chemically attached to the backbone of the polyurethane polymer matrix with a bifunctional monomer. Since silver is one of the most effective antibacterial agents with low toxicity used for its high degree of biocompatibility and its long-term antibacterial effectiveness against many different bacterial strains, it was also examined as a TiO₂ dopant. The quantitative examination of bacterial activity was determined by the survival ratio as calculated from the number of viable cells, which form colonies on the petri dishes with nutrient agar. Good inhibition results were observed and demonstrated visually with close to 97% of bacteria killed after 2 hours. In summary the functionalized nTiO₂/PU, and silver doped nTiO₂/PU  composite coatings displayed considerable antibacterial activity against both gram-positive and gram-negative bacteria under UV irradiation while silver doped nTiO₂/PU coatings displayed considerable antibacterial activity even under irradiation of visible light.