Backgroun d and Aim: Nanotechnology has made a significant contribution to Photodynamic inactivation (PDI), as one of the promising alternative treatments to combat biofilm. The effectiveness of PDI using fullerene nanoparticle (as a photosensitizer) can be improved by development of innovative multifunctional nanosystems. Here we aimed to evaluate photodynamic inactivation of Pseudomonas aeruginosa biofilm using a novel nano - based photosensitizer (a hybrid nanosystem composed of silver, silica and fullerene).
Method s: Ag/SiO2 co - doped fullerene nanosystem was synthesized by chemical vapor deposition (CVD) method. 24 - h - old biofilms of P. aeruginosa were treated with the nanosystem for 10 min and subsequently exposed to white light from a light - emitting diode (LED) at f luence of 42.2 J/cm2. Appropriate controls were included. Biofilm metabolic activity was quantified by colorimetry with a tetrazolium reduction assay to measure live bacteria after the treatments. To determine the effect of PDI on P. aeruginosa biofilm str ucture, three - dimensional (3D) morphology and surface of biofilm was investigated by atomic force microscopy (AFM).
Results: Ag/SiO2 co - doped fullerene nanosystem - mediated PDI significantly reduced the metabolic activity of biofilm of P. aeruginosa ( ∼ 100%). In the absence of light, the nanosystem did not significantly impair biofilm metabolic activity ( ∼ 3%). An analysis of the AFM topography 3D - images showed that Ag/SiO2 co - doped fullerene nanosystem - mediate PDI induced severe morphological and surface alter ations (loss of the typical cell morphology and increase in surface roughness, respectively) of biofilm.
Conclusion: In conclusion, Ag/SiO2 co - doped fullerene nanosystem - mediated PDI offer a new modality for fast and efficient destruction of P. aeruginosa biofilm, suggesting its potential use in chronic wound healing.