Coogan, Michael and Court, Jonathan B. and Gray, Victoria L. and Hayes, Anthony J. and Lloyd, Siôn H. and Millet, Coralie and Pope, Simon J. A. and Lloyd, David (2010) Probing intracellular oxygen by quenched phosphorescence lifetimes of nanoparticles containing polyacrylamide-embedded [Ru(dpp(SO3Na)2)3]Cl2. Photochemical and Photobiological Sciences, 9 (1). pp. 103-109. ISSN 1474-905X
Full text not available from this repository.Abstract
Methods for measuring O2 within living cells that rely on luminescent probes are hampered by several factors: local conditions of hydrophobicity, pH, ionic composition, dielectric constant, and photobleaching by free radical species. Use of a polymer-embedded luminophore should minimize these problems. Here we use a Ru(II) coordination complex embedded within 45 nm hydrodynamic diameter nanoparticles, and demonstrate that both phosphorescence intensity and lifetimes are O2-sensitive, both in aqueous suspensions and intracellularly (e.g. 4.06 versus 1.55 microseconds under anaerobic or aerobic conditions, respectively). Electroporation is necessary for incorporation of the nanoparticles into yeasts: it is more effective with the fission yeast, Schizosaccharomyces pombe, than for the budding yeast, Saccharomyces cerevisiae. However, electroporation was not required for particle uptake into a cultured human cell-line (mammary adenosarcoma MCF-7), although the intracellular distribution of the probe is more general to intracellular compartments when electroporation is employed. These procedures did not compromise vitality of cells over periods of 6 h, as judged by retention of structural characteristics evident in Nomarski interference or confocal microscopy images. Spatial resolution of intracellular structures defined by nanoparticle phosphorescence intensity imaging indicates potential usefulness of the application of lifetime imaging techniques for mapping of intracellular O2 distributions.