  Heat transfer and dissipation exists in almost any physical, chemical or
biological systems. Cells, as the basic unit of life, undergo continuous heat
transfer and dissipation during their metabolism. The heat transfer and
dissipation within cells related to not only fundamental cellular functions and
biochemical reactions, but also several important applications including
heat-induced control of biological processes and treatment of diseases.
Unfortunately, thus far, we still know very little about the heat transfer and
dissipation properties at cellular or subcellular level. Here, we demonstrated
a methodology of transient microscopy to map the heat transfer coefficients in
single cells, with a temporal resolution of ~5 us and a spatial resolution of
~250 nm (close to diffraction limit). The heat transfer coefficients of
different location within single cells were obtained for the first time, the
inner part of cells exhibited nonuniform heat transfer properties, and it
suggested a self-consistent heat transfer regulation that responds to
environmental temperature.
