A tiny diamond-based sensor just 1/50,000th of a millimetre across can be used to measure the temperature at specific points inside cells, scientists have shown.
Writing in Nature, Harvard scientist Georg Kuscko and his colleagues have discovered that tiny diamond particles containing nitrogen atoms in place of some of the normal carbon atoms can function as miniature thermometers.
Placed inside cells, these crystals can provide a temperature readout with a precision of 1/500th of a degree.
When illuminated by green light, the part of the crystal containing the nitrogen atom vibrates and releases the energy as red light, the intensity of which changes with temperature. This is because, as the temperature changes, it alters the stiffness of the crystal lattice, which in turn affects the light production, which can be measured.
Most cells are highly compartmentalised with multiple energy-producing and energy-consuming reactions happening in specific areas.
Probes based on these nanodiamond thermometers will enable cell biologists to begin to understand much better the flow of energy within cells as well as uncovering ways to deliberately manipulate temperature to alter cell behaviour, perhaps as an anti-cancer therapy.