title: Intracellular temperature mapping with a fluorescent polymeric thermometer and fluorescence lifetime imaging microscopy.
abstract: Cellular functions are fundamentally regulated by intracellular temperature, which influences biochemical reactions inside a cell. Despite the important contributions to biological and medical applications that it would offer, intracellular temperature mapping has not been achieved. Here we demonstrate the first intracellular temperature mapping based on a fluorescent polymeric thermometer and fluorescence lifetime imaging microscopy. The spatial and temperature resolutions of our thermometry were at the diffraction limited level (200 nm) and 0.18-0.58 °C. The intracellular temperature distribution we observed indicated that the nucleus and centrosome of a COS7 cell, both showed a significantly higher temperature than the cytoplasm and that the temperature gap between the nucleus and the cytoplasm differed depending on the cell cycle. The heat production from mitochondria was also observed as a proximal local temperature increase. These results showed that our new intracellular thermometry could determine an intrinsic relationship between the temperature and organelle function.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Kohki
authors.initials: K
authors.lastname: Okabe
authors.forename: Noriko
authors.initials: N
authors.lastname: Inada
authors.forename: Chie
authors.initials: C
authors.lastname: Gota
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Harada
authors.forename: Takashi
authors.initials: T
authors.lastname: Funatsu
authors.forename: Seiichi
authors.initials: S
authors.lastname: Uchiyama
mesh_terms: D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002467:Cell Nucleus / Q000502:physiology*; D018385:Centrosome / Q000502:physiology; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence / Q000379:methods*; D013696:Temperature; D013821:Thermometers