Proc. Natl Acad. Sci. USA doi:10.1073/pnas.1002562107 (2010)

Ion channels have a central role in biology, controlling the movement of ions across cell membranes. A range of techniques are used to probe the workings of ion channels but these methods can have various problems such as being unstable or difficult to scale up. Now a team of researchers from Australia and Germany has proposed that it should be possible to study ion channels in real time by monitoring how ions moving through these channels can influence the quantum properties of a nitrogen vacancy in a nearby nanodiamond.

Liam Hall of the University of Melbourne and co-workers propose placing the nanodiamond on the tip of an atomic force microscope, which is then brought to within a few nanometres of the lipid bilayer that contains the ion channels. A combination of optical and microwave pulses are used to drive the nitrogen vacancy into a quantum coherent state. Such states are very fragile and they rapidly lose coherence as a result of interactions with their environment. However, despite there being many sources of decoherence in the cellular milieu, Hall and co-workers have calculated that it should be possible to quantify that caused by the operation of the ion channels.