Quantum dot nano thermometers reveal heterogeneous local thermogenesis in living cells.

The local temperature response inside single living cells upon external chemical and physical stimuli was characterized using quantum dots as nano thermometers. The photoluminescence spectral shifts from endocytosed quantum dots were used to map intracellular heat generation in NIH/3T3 cells following Ca(2+) stress and cold shock. The direct observation of inhomogeneous intracellular temperature progression raises interesting new possibilities, including further innovations in nanomaterials for sensing local responses, as well as the concept of subcellular temperature gradient for signaling and regulation in cells.