Direct detection of airborne singlet oxygen from porous Vycor glass particles adsorbed with a brominated BODIPY photosensitizer

ANDRES M. DURANTINI; ALEXANDER GREER

Conferencia; ACS National Meeting & Exposition; 2020

We present a physical organic study of an 8-acetoxymethyl-2,6-dibromo BODIPY photosensitizer (PS) dispersed onto ground porous Vycor glass (PVGPS) for the production of airborne singlet oxygen (1O2). Green-light photosensitization of dry PVGPSparticles led to the direct detection of 1O2 phosphorescence at 1270 nm. Decay curves for singlet oxygen show two lifetimes (τ1 and τ2). A short lifetime (τ1 = 68 μs) was attributed to 1O2 residing at the air/PVGPS surface with some spurious light that scattered and reached the near IR detector (Figure). However, the long lifetime (τ2 = 1810 μs) was attributed to airborne 1O2. Also, experiments adding a 1O2 chemical quencher (9,10-anthracene dipropionic acid, Q) adsorbed on separate PVG particles or the 1O2 physical quencher (H2O surface) caused τ2 to disappear. Finally, the presence of airborne 1O2 was assessed by conducting experiments in anaerobic conditions. Upon pre-purging the PVGPS with nitrogen, the 1270-nm signal intensity drops significantly. Further, after purging the sample with molecular oxygen (re-oxygenation) the lifetimes were restored. Our results provide insight on how airborne 1O2 may be exploited to eradicate dry biofilms in healthcare settings.