The high incidence of hospital-acquired infection (HAI) is an extremely topical problem, constantly piquing media interest. In the U.K. it has been approximated that the treatment of these infections annually cost NHS hospitals over �1 billion. One strategy to reduce the spread of infection in healthcare environments is the use of self-sterilising surfaces. This technology can be applied to a range of touch surfaces, to help disrupt the cycle of transmission of bacteria from surfaces-to-patients or surfaces-to-healthcare workers. The use of antimicrobial surfaces in medical devices such as urinary catheters can also potentially reduce the incidence of associated infection. A novel approach that can be utilised across a wide range of surfaces is the use of a modified form of photodynamic therapy. A �swell-encapsulation-shrink� technique was used to incorporate the light-activated antimicrobial agents, crystal violet and methylene blue, in addition to 2 nm nanogold, into medical grade silicone. The samples were tested against Staphylococcus epidermidis and Escherichia coli. These surfaces induced the lethal photosensitisation of both bacteria upon activation with either a low power red laser for short illumination time periods (13.5 minutes), or a white hospital lighting source over a lengthier illumination time period. Under both irradiation regimes, when tested against S. epidermidis, bacterial numbers were reduced below the detection limit. When tested against E. coli, a 2.6 log reduction in bacterial numbers was noted after laser irradiation (635 nm) and bacterial numbers were reduced below the detection limit under white light illumination conditions within 6 hours. These samples also demonstrated significant antimicrobial activity under dark conditions, against both bacteria tested. Ultimately, it is hopeful that this efficacious photo-activated antimicrobial activity can be harnessed in healthcare applications, for use in both hospital surfaces and in medical devices, to help combat and lower the rates of contraction of associated infections.

Antimicrobial surfaces for healthcare applications

248th National Meeting (2014)

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