Chemical synthesis and characterization of nanostructured tiO2 based composites studies on their potential biomedical applications

Abstract

Mesoporous AgCl TiO2 nanoparticles (ATNPs) with Titanium dioxide (TiO2) as the newlinehomogenous anatase crystalline phase were synthesized using a one pot sol gel newlinemethod. The sample was calcined at 100 °C and characterized by X ray diffraction, newlineHigh resolution transmission electron microscopy, Energy dispersive X ray newlinespectroscopy, Fourier transform infrared spectroscopy, Diffuse reflection spectroscopy, newlineN2 adsorption desorption isotherm and Brunauer Emmett Teller (BET) analysis. The newlineBET surface area and crystallite size of ATNPs were determined to be 266 m2/g and newline3.76 nm respectively. The ATNPs exhibited excellent antimicrobial activity against newlinerepresentative Gram positive and Gram negative bacterial cultures and Candida newlinealbicans. Complete inhibition of microorganisms was achieved at a very low ATNP newlineconcentration, in the range of 1.0 to 20 and#956;g/mL (effective Ag concentrations were 11.7 newlineto 234 ppb) in less than 2 h under ambient conditions. Silver ion release studies showed newlinethat about 18 % of total silver incorporated in TiO2 was present as silver ions in newlinesolution, indicating that the antimicrobial activity is due to silver ions released from the newlineTiO2 matrix. newlineAs most microorganisms are present as biofilms, these ATNPs were further tested for newlinetheir anti-biofilm activity. Sol gel coatings of ATNPs presented as potential antibiofilm newlineagents, wherein TiO2 acted as a good supporting matrix to prevent aggregation newlineof silver and facilitated its controlled release. Low temperature processed ATNP newlinecoatings inhibited biofilm formation by Escherichia coli, Staphylococcus epidermidis newlineand Pseudomonas aeruginosa. In vitro biofilm assay experiments demonstrated that newlineATNP coated surfaces, inhibited the development of biofilms over a period of 10 days newlineas confirmed by Scanning electron microscopy (SEM). The silver release kinetics newlineexhibited an initial high release, followed by a slow and sustained release. The anti newlinebiofilm efficacy of the coatings could be attributed to the release of silver ions, which newlineprevents the initial bacterial adhesio