Gold Nanorod-Functionalised Surfacesfor Bacterial Elimination - Utilising localised surface plasmon resonance generated heat to prevent implant-associated infections

Examensarbete för masterexamen
Ridderstråle, Caroline
Medical implant-associated infections are a major problem in today’s healthcare. A big issue is microbial contamination of the implant during surgery, since it often is the start of implant-associated infections. Control of the hospitalisation environment and use of antibiotics have been a key target to minimise the risk of infection during implant surgeries. However, a possible alternative way to inhibit microbial adhesion and growth of bacteria on the implant is to modify the chemistry or the topology of the implant surface. Therefore, to be able to prevent implant-associated infections, the development of new materials is important. A procedure for making use of gold nanorod-functionalised surfaces that are irradiated with near-infrared (NIR) light to photothermally eliminate bacteria in contact with the surfaces has been developed and evaluated in this thesis. The gold nanorod-functionalised surfaces were produced by electrostatic surface assembly of gold nanorods on glass surfaces, and the used gold nanorods were synthesised through a seed-mediated synthesis. Two types of in vitro studies were conducted to evaluate the antimicrobial activity of the gold nanorod-functionalised glass surfaces irradiated with NIR light at 808 nm. From both of the in vitro studies the results indicated that a surface with gold nanorods irradiated with NIR light can photothermally eliminate bacteria in contact with the surface. One study contained exposure of the surfaces in a laboratory room to collect microbial contamination on the surfaces, to mimic the exposure of an implant during a surgical procedure. This study also showed that a surface with gold nanorods attracts more particles with bacteria compared to a glass surface, likely due to the electrostatic charge of the gold nanorods. The other in vitro study used Staphylococcus aureus cultured and partly dried on the surfaces. Approximately 22 % more dead bacteria were detected on the surfaces irradiated with NIR light compared to the control surfaces. The concept of utilising gold nanorod-functionalised surfaces in combination with NIR light to help fight and prevent implant-associated infections showed promise for future work. It would further be interesting to find an optimum of antimicrobial activity by varying the gold nanorod surface coverage and the power of the NIR laser. Furthermore it would be interesting to expose surfaces in operating rooms for implants, to evaluate the elimination of the microbial contamination occurring in a clinical environment.
Gold nanorods, implant-associated infections, localised surface plasmon resonance, antimicrobial surfaces
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