Bacteriophage inactivation by UV-A illuminated fullerenes: role of nanoparticle-virus association and biological targets.

Inactivation rates of the MS2 bacteriophage and (1)O(2) generation rates by four different photosensitized aqueous fullerene suspensions were in the same order: aqu-nC(60) < C(60)(OH)(6) ≈ C(60)(OH)(24) < C(60)(NH(2))(6). Alterations to capsid protein secondary structures and protein oxidation were inferred by detecting changes in infrared vibrational frequencies and carbonyl groups respectively. MS2 inactivation appears to be the result of loss of capsid structural integrity (localized deformation) and the reduced ability to eject genomic RNA into its bacterial host. Evidence is also presented for possible capsid rupture in MS2 exposed to UV-A illuminated C(60)(NH(2))(6) through TEM imagery and detection of RNA infrared fingerprints in ATR-FTIR spectra. Fullerene-virus mixtures were also directly visualized in the aqueous phase using a novel enhanced darkfield transmission optical microscope fitted with a hyperspectral imaging (HSI) spectrometer. Perturbations in intermolecular extended chains, HSI, and electrostatic interactions suggest that inactivation is a function of the relative proximity between nanoparticles and viruses and (1)O(2) generation rate. MS2 log survival ratios were linearly related to CT (product of (1)O(2) concentration C and exposure time T) demonstrating the applicability of classical Chick-Watson kinetics for all fullerenes employed in this study. Results suggest that antiviral properties of fullerenes can be increased by adjusting the type of surface functionalization and extent of cage derivatization thereby increasing the (1)O(2) generation rate and facilitating closer association with biological targets.