title: Temperature changes in brown adipocytes detected with a bimaterial microcantilever.
abstract: Mammalian cells must produce heat to maintain body temperature and support other biological activities. Methods to measure a cell's thermogenic ability by inserting a thermometer into the cell or measuring the rate of oxygen consumption in a closed vessel can disturb its natural state. Here, we developed a noninvasive system for measuring a cell's heat production with a bimaterial microcantilever. This method is suitable for investigating the heat-generating properties of cells in their native state, because changes in cell temperature can be measured from the bending of the microcantilever, without damaging the cell and restricting its supply of dissolved oxygen. Thus, we were able to measure increases in cell temperature of <1 K in a small number of murine brown adipocytes (n = 4-7 cells) stimulated with norepinephrine, and observed a slow increase in temperature over several hours. This long-term heat production suggests that, in addition to converting fatty acids into heat energy, brown adipocytes may also adjust protein expression to raise their own temperature, to generate more heat. We expect this bimaterial microcantilever system to prove useful for determining a cell's state by measuring thermal characteristics.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan.
authors.forename: Masaaki K
authors.initials: MK
authors.lastname: Sato
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Toda
authors.affiliation: Micro System Integration Center, Tohoku University, Sendai, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Inomata
authors.affiliation: Department of Micro-Nano Systems Engineering, Nagoya University, Nagoya, Japan.
authors.forename: Hisataka
authors.initials: H
authors.lastname: Maruyama
authors.affiliation: Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Okamatsu-Ogura
authors.affiliation: Department of Micro-Nano Systems Engineering, Nagoya University, Nagoya, Japan.
authors.forename: Fumihito
authors.initials: F
authors.lastname: Arai
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai, Japan.
authors.forename: Takahito
authors.initials: T
authors.lastname: Ono
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ishijima
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan. Electronic address: inoue@tagen.tohoku.ac.jp.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D052437:Adipocytes, Brown / Q000378:metabolism*; D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002478:Cells, Cultured; D004734:Energy Metabolism; D006046:Gold / Q000737:chemistry; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D017655:Silicon Compounds / Q000737:chemistry; D059010:Single-Cell Analysis / Q000295:instrumentation / Q000379:methods*; D013696:Temperature; D013821:Thermometers; D062125:Thermometry / Q000295:instrumentation / Q000379:methods*
chemical_list: D017655:Silicon Compounds; D006046:Gold; C032734:silicon nitride