title: Sulforhodamine Nanothermometer for Multiparametric Fluorescence Lifetime Imaging Microscopy.
abstract: Live cells function within narrow limits of physiological temperature (T) and O2and metabolite concentrations. We have designed a cell-permeable T-sensitive fluorescence lifetime-based nanoprobe based on lipophilic sulforhodamine, which stains 2D and 3D cell models, shows cytoplasmic localization, and has a robust response to T (∼0.037 ns/K). Subsequently, we evaluated the probe and fluorescence lifetime imaging microscopy (FLIM) technique for combined imaging of T and O2gradients in metabolically active cells. We found that in adherent 2D culture of HCT116 cells intracellular T and O2are close to ambient values. However, in 3D spheroid structures having size >200 μm, T and O2gradients become pronounced. These microgradients can be enhanced by treatment with mitochondrial uncouplers or dissipated by drug-induced disaggregation of the spheroids. Thus, we demonstrate the existence of local microgradients of T in 3D cell models and utility of combined imaging of O2and T.
authors.affiliation: School of Biochemistry and Cell Biology, University College Cork , Cork, Ireland.
authors.forename: James
authors.initials: J
authors.lastname: Jenkins
authors.affiliation: Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology , 8010 Graz, Austria.
authors.forename: Sergey M
authors.initials: SM
authors.lastname: Borisov
authors.affiliation: School of Biochemistry and Cell Biology, University College Cork , Cork, Ireland.
authors.forename: Dmitri B
authors.initials: DB
authors.lastname: Papkovsky
authors.affiliation: School of Biochemistry and Cell Biology, University College Cork , Cork, Ireland.
authors.forename: Ruslan I
authors.initials: RI
authors.lastname: Dmitriev
mesh_terms: D045325:HCT116 Cells; D006801:Humans; D008856:Microscopy, Fluorescence / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D010100:Oxygen / Q000378:metabolism; D012235:Rhodamines / Q000737:chemistry*; D018874:Spheroids, Cellular / Q000378:metabolism; D013696:Temperature; D013821:Thermometers
chemical_list: D012235:Rhodamines; C022027:lissamine rhodamine B; D010100:Oxygen