Bacteriophage inactivation by UV-A illuminated fullerenes: Role of nanoparticle-virus association
A significant potential for nanoparticle incorporation into water treatment applications has focused on bacteria and virus inactivation due to singlet oxygen generation. Photosensitization of hydrophilic fullerenes generates singlet oxygen (1O2), and this has been shown to inactivate bacteriophages in aqueous environments. Here, four fullerene nanoparticle (FNP) suspensions with varying surface functional groups are investigated with respect to 1O2 generation and virus inactivation. We hypothesize that the rate of virus inactivation by photosensitized fullerenes is controlled by their relative proximity as well as the 1O2 generation rates. The limited data available in the literature supports this assertion though direct evidence has not yet been provided. Bacteriophage MS2 was inactivated by 1O2 in four FNP suspensions, and inactivation rates followed the trend: aqu-nC60 < C60(OH)6 < C60(OH)24 < C60(NH2)6. This trend is discussed considering both 1O2 generation, measured using Singlet Oxygen Sensor Green (SOSG) and the relative proximity between nanoparticles and viruses. The distance between nanoparticles and viruses was directly visualized with a dark-field transmission optical microscope fitted with a hyperspectral imaging (HSI) spectrometer in the aqueous phase and confirmed with TEM images. These findings imply that future studies of FNP use in water treatment applications would benefit from surface modifications that enhance nanoparticle affinity for biological targets. © 2012 American Water Works Association AWWA WQTC Conference Proceedings.
