Fluorescent polymer thermometer maps temperature differences in cells

Scientists in Japan have developed a new fluorescent polymer thermometer which can map the temperature differences in different portions of living cells.

The new equipment has shown some organelles within cells are warmer than others, and could help understand how cells regulate their temperature and how this correlates with disease. Seiichi Uchiyama and his team from the University of Tokyo have already developed a fluorescent polymer that can determine the average temperature of whole cells, but they redesigned the whole system in order to see what was going on at a sub-cellular level.

The previous polymer took the cell's temperature as aggregate, rather than dispersing itself throughout the cell. Takashi Uchiyam, from the University of Tokyo, commented in RSC: "We improved the solubility of the thermometer by making it more hydrophilic.

"In addition, the resultant thermometer was small enough to enter the nucleus."

The thermometer incorporates three elements into a copolymer: a fluorescent molecule, hydrophilic groups and a heat-responsive portion. The fluorescence is quenched by water, but as the polymer contracts in response to increased temperature, the water is displaced and the fluorescence response increases. A key modification for mapping temperature in different parts of a cell, says Uchiyama, was switching from measuring the fluorescence intensity to fluorescence lifetime.

Posted by Ben Evans