Inside-out Ultraviolet-C Sterilization of Pseudomonas aeruginosa Biofilm In Vitro.

Biofilms are difficult to eradicate due to a protective architecture and create major challenges in patient care by diminishing both host immune response and therapeutic approaches. This study investigated a new strategy for treating surface-attached biofilms by delivering germicidal UV through a material surface in a process referred to as "inside-out sterilization" (IOS). Mature Pseudomonas aeruginosa (ATCC 27853 ) biofilms were irradiated with up to 1400 mJ cm of germicidal UV from both ambient and IOS configurations. The lethal dose for the ambient exposure group was 461 mJ cm 95% CI [292, 728] compared to the IOS treatment group of 247 mJ cm 95% CI [187, 325], corresponding to 47% less UV dosage for the IOS group (P < 0.05). This study demonstrated that with IOS, a lower quantal dosage of UV energy is required to eradicate biofilm than with ambient exposure by leveraging the organizational structure of the biofilm.