Tiny thermometers used in living cells

Abstract

Nanometre-scale thermometers that operate with millikelvin sensitivity have now been made from diamond crystals. The devices have been used to measure temperature gradients in living cells. See Letter p.54 A nanoscale thermometer capable of subdegree temperature resolution and of integration within living cells could provide a powerful new tool for many areas of biological and medical research. This paper describes a new probe for nanoscale thermometry that achieves just that. The device uses quantum manipulation of nitrogen–vacancy colour centres in diamond nanocrystals. These harbour single electron spins and have specific fluorescence properties that are sensitively dependent on the local temperature. The authors show that they can be accurately measured with a spatial resolution down to 200 nm. By introducing both nanodiamonds and gold nanoparticles into a single human embryonic fibroblast, they demonstrate temperature-gradient control and mapping at the subcellular level.