USE OF ANTIMICROBIAL POLYMERS AS A NOVEL ANTIFUNGAL APPROACH AGAINST CANDIDA ALBICANS BIOFILMS
Jason Joyner1 Aaron Neumann2.
1University of Nevada Reno, Reno, NV, 2University of New Mexico, Albuquerque, NM.
The fungal pathogen, Candida albicans, is the fourth most common cause of nosocomial bloodstream infections worldwide. Increased drug resistance provided by formation of fungal biofilms limits the effectiveness of current antifungal drugs. We employed a new approach by using poly(phenylene ethynylene)-DABCO (PPE-DABCO), a non-toxic, photoactivated antimicrobial polymer, to determine its ability to enter and kill pathogens throughout fungal biofilm. PPE-DABCO can kill yeast in suspension cultures, but it is unclear how well it will penetrate thick biofilm structures. We added a lethal dose (20 ug/ml) of PPE-DABCO or control Alexa Fluor 405 (AF405) at 100 uM to C. albicans biofilms and measured diffusion of the compound into the film over 2 hours. The t1/2 of PPE-DABCO infiltration into the biofilm was 10 fold longer than AF405 infiltration when compared to non-biofilm diffusion. These results suggest PPE-DABCO interacts with the biofilm, but still allows for penetration. After 3 hours of binding, PPE-DABCO will be stimulated by 405 nm light, releasing reactive oxygen species. The killing efficiency of PPE-DABCO will be quantified by fluorescence of a DNA dye, DRAQ7. If greater fluorescence is measured in cells treated with PPE-DABCO than the untreated control, killing ability will be confirmed. PPE-DABCO diffuses through C. albicans biofilm, indicating the electrostatic interaction as a positive characteristic for a compound diffusing through biofilm. Cell killing in C. albicans biofilm will continue to be studied, and if both are confirmed as expected, the traits of the compound can be used to further explore development of an effective, non-toxic anti-biofilm drug.