title: Imaging intracellular viscosity by a new molecular rotor suitable for phasor analysis of fluorescence lifetime.
abstract: The arsenal of fluorescent probes tailored to functional imaging of cells is rapidly growing and benefits from recent developments in imaging strategies. Here, we present a new molecular rotor, which displays strong absorption in the green region of the spectrum, very little solvatochromism, and strong emission sensitivity to local viscosity. The emission increase is paralleled by an increase in emission lifetime. Owing to its concentration-independent nature, fluorescence lifetime is particularly suitable to image environmental properties, such as viscosity, at the intracellular level. Accordingly, we demonstrate that intracellular viscosity measurements can be efficiently carried out by lifetime imaging with our probe and phasor analysis, an efficient method for measuring lifetime-related properties (e.g., bionalyte concentration or local physicochemical features) in living cells. Notably, we show that it is possible to monitor the partition of our probe into different intracellular regions/organelles and to follow mitochondrial de-energization upon oxidative stress.
authors.affiliation: NEST, Scuola Normale Superiore and Istituto Nanoscienze, CNR, Pisa, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Battisti
authors.forename: Silvio
authors.initials: S
authors.lastname: Panettieri
authors.forename: Gerardo
authors.initials: G
authors.lastname: Abbandonato
authors.forename: Emanuela
authors.initials: E
authors.lastname: Jacchetti
authors.forename: Francesco
authors.initials: F
authors.lastname: Cardarelli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Signore
authors.forename: Fabio
authors.initials: F
authors.lastname: Beltram
authors.forename: Ranieri
authors.initials: R
authors.lastname: Bizzarri
mesh_terms: D002460:Cell Line; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D042541:Intracellular Space / Q000737:chemistry*; D007700:Kinetics; D008856:Microscopy, Fluorescence / Q000295:instrumentation* / Q000379:methods; D014783:Viscosity
chemical_list: D005456:Fluorescent Dyes