Another front in the war against infection is the introduction of antimicrobial surfaces into hospitals.
By making the environment more hostile to pathogens such as Clostridium difficile and Staphilococcus aureus there will be less chance that they will be spread around by casual contacts. Surfaces such as beds, door handles, pens and keyboards are possible sources of transfer. Professor Ivan Parkin of UCL, part of a team working on antimicrobial dyes which work in low light levels and even in the dark, said: “There are certain dyes that are known to be harmful to bacteria when subjected to bright light. “The light excites electrons in them, promoting the dye molecules to an excited triplet state and ultimately produces highly reactive oxygen radicals that damage bacteria cell walls.
“Our project tested new combinations of these dyes along with gold nanoparticles, and simplified ways of treating surfaces which could make the technology easier and cheaper to roll out.” Tests which subjected silicone infused with crystal violet, methylene blue and gold nanoparticles to infection shoed the most potent antibacterial effect ever observed in such a surface while having no significant effect on the properties of the silicone. Sacha Noimark, lead author of the paper which reported the results, said: “Despite contaminating the surface with far more bacteria than you would ever see in a hospital setting, placed under a normal florescent light bulb, the entire sample was dead in three to six hours, depending on the type of cacteria.
“That was an excellent result, but the bigger surprise was the sample which we left in the dark. That sample, too, showed significant reductions in bacterial load, albeit over longer timescales of about three to eighteen hours.”