Temperature mapping of living HeLa cells.

<p>A) Confocal fluorescence images and fluorescence lifetime images of the cell-permeable FPT in a HeLa cell. N indicates the nucleus (the area of the nucleus is indicated by a dotted line). B) Histograms of the fluorescence lifetime in the nucleus (red) and in the cytoplasm (blue) in a cell in A. C) Histogram of the temperature difference between the nucleus and the cytoplasm (<i>n</i> = 49). The temperature difference (<<i>ΔT</i>>) was calculated by subtracting the average temperature of the cytoplasm from that of the nucleus. The temperature of the medium was maintained at 30°C. Scale bar = 10 µm.