Introduction: Both urinary tract infections and primary bloodstream infections result from the use of PDMS catheters and are reported to be the most common nosocomial infections. Despite disinfection procedures used in hospitals, infections still occur, causing delays in discharge and potential mortalities. Bimetallic AgCu nanoparticles (AgCuNPs) are found to exhibit antimicrobial activity against pathogens. Hence, this work reports a manufacturing procedure for fabricating antimicrobial AgCu-PDMS films, which was shown to effectively reduce microbial growth of bacteria and fungi.
Methods: AgCuNP (0.1 % wt/v) was dispersed in Sylgard™ silicone elastomer curing agent and then added to the silicone elastomer base. The mixture was heat-cured and cast, forming 0.1 mm thin films. The fabricated AgCu-PDMS films were treated with a UV254 or UV365 light source for 15 min. SEM was used to characterise the films, and the population of NP exposured was semi-quantified using ImageJ. Microbial broths (x104) were loaded onto the AgCu-PDMS films, and kinetic growth measurements were conducted to evaluate the antimicrobial properties against E. coli, S. aureus, and C. albicans.
Results and Discussion: Despite the higher frequency exhibited by the UV254, more than double of the AgCuNPs were found exposed on the PDMS surface after etching the film using the UV365 source. This can be explained by the photothermal property owned by this bimetallic nanomaterial, which shows a board surface plasmonic resonance at λmax (410 nm) and resulted in excessive polymer degradation due to the excitation of the nanoparticles. Therefore, as expected, the antimicrobial results obtained from the UV365-treated AgCu-PDMS films achieved the optimal 72% reduction of microbial growth in relation to the control.
Conclusions: PDMS polymer with incorporated AgCuNPs exhibited antimicrobial properties after UV subjection to expose nanoparticles. Whilst it shows potential to challenge catheter infections, toxicity tests are required to research the suitability of these PDMS films for biomedical applications.
