Bactericidal performance of photocatalytic titanium dioxide particle mixture under ultraviolet and fluorescent light: an in vitro study

Bactericidal Activity of Aqueous Acrylic Paint Dispersion for Wooden Substrates Based on TiO₂ Nanoparticles Activated by Fluorescent Light

The photocatalytic effect of TiO₂ has great potential for the disinfection of surfaces. Most studies reported in the literature use UV activation of TiO₂, while visible light has been used only in a few applications. In these studies, high concentrations of TiO₂, which can compromise surface properties, have been used. In this work, we have developed an acrylic-water paint dispersion containing low TiO₂ content (2 vol %) for the inactivation of microorganisms involved in hospital-acquired infections. The nanoparticles and the coating have been characterized using spectroscopic techniques and transmission electron microscopy, showing their homogenous dispersion in the acrylic urethane coating. A common fluorescent light source was used to activate the photocatalytic activity of TiO₂. The paint dispersion showed antimicrobial activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The coating containing the TiO₂ nanoparticles maintained good UV stability, strong adhesion to the substrate and high hardness. Therefore, the approach used is feasible for paint formulation aimed at disinfection of healthcare surfaces.

Mitigation of Staphylococcus aureus-mediated surgical site infections with ir photoactivated TiO2 coatings on Ti implants

Surgical site infections caused by methicillin-resistant and methicillin-susceptible Staphylococcus aureus (MRSA, MSSA) lead to patient hospitalization for an extended period coupled with concomitant hospitalization resources and cost. The detrimental effect resulting from the onset of these infections poses great health risks, leading to death in some instances. Titanium dioxide (TiO(2) ) is endowed with the unique capability of photoactivity which has been extensively exploited in antibacterial activities. It has been shown to be very effective in its bactericidal efficacy against infection-causing bacterial strains, namely, E. coli and S. aureus. In this study, the use of IR-photoactivated TiO(2) nanocoatings on titanium implants to mitigate the onset of surgical site infections is described. TiO(2) coatings were created on implantable materials by way of an aqueous plasma electrodeposition technique and were used to mitigate the harmful bacterial growth upon brief activation by an infrared (IR) laser source. The necrosis of S. aureus cells was found to exceed 90% within 30 min. following a 30s exposure of the titania-coated model implants (Ti mesh and plate). Promising potential of antibacterial coatings in mitigating surgical site infections has been shown.

Necrosis of Staphylococcus aureus by the Electrospun Fe- and Ag-Doped TiO2 Nanofibers

Postsurgery infections cause prolonged hospitalization, incurring increased patient and hospital costs, making it increasingly vital to develop an effective solution for the mitigation and elimination of infection buildup at these sites. Incorporation of a bactericidal device at the infection-prone sites provides the capability of attacking bacterial growth even after the patient has left the hospital. Polycrystalline titanium dioxide (TiO₂) is photoactive and possesses antibacterial properties that can mitigate the onset of these infections and aid in wound healing. In this work, TiO₂ nanofibers were synthesized by electrospinning. Doping with iron as well as with silver (5 wt% and 1 wt%, resp.) was also carried out to increase their effectiveness towards bactericidal properties. The electrospun fibers were processed and tested in the presence of light in the suspensions of methicillin-susceptible Staphylococcus aureus (MSSA) bacteria, which are the leading infection-inducing bacteria among hospital patients. It was found that upon brief activation (cf. 30 s) by an infrared laser source, greater than 90% of the S. aureus was rendered inactive within cf. 10 min. of exposure, thereby showing the potential of titania nanofibers for effective mitigation of infection.

Infection mitigation efficacy of photoactive titania on orthopedic implant materials

In order to impede infection and achieve accelerated wound healing in the postorthopaedic surgery patients, a simple and benign procedure for creating nanotubular or nanofibrillar structure of photoactive TiO₂ on the surface of Ti plates and wires is described. The nanoscale TiO₂ films on titanium were grown by hydrothermal processing in one case and by anodization in the presence of dilute mineral acids under mild and benign conditions in the other. Confocal microscopy results demonstrated at least 50% reduction in the population of E. coli colonies (concentration 2.15 × 10⁷ cells/mL) on TiO₂-coated implants upon an IR exposure of up to 30 s; it required ∼20 min of exposure to UV beam for the same effect. These findings suggest the probability of eliminating wound infection during and after orthopedic surgical procedures by brief illumination of photoactive titania films on the implants with an IR beam.