Nature Commun. 5, 3735 (2014)

Our body's natural sensors are adept at distinguishing chiral molecules, but artificial systems still fall short on this count, particularly when the molecules in question are in a vapour phase. Man-made sensors for environmental and pharmaceutical applications would clearly benefit from the sophisticated chiral discrimination boasted by our olfactory perception machinery. And now, Takuya Ohzono and co-workers have succeeded in realizing an effective chiral sensor.

Some nematic liquid crystals exhibit detectable changes in alignment in the presence of chiral molecules, but when dissolved in gas, the molecules are so small that the change is difficult to make out. The problem is compounded by the fact that the liquid crystals in existing chiral sensors are generally bounded by a solid or liquid interface, which affects the way that the molecules are incorporated.

The chiral sensor devised by Ohzono et al. exploits a structural change in the periodic microstructure of a nematic liquid crystal, confined in a microchannel in such a way as to enhance the change. Their set-up also allows rapid dissolution of the vapour molecules, making for a simple, fast and highly sensitive process, operable at ambient temperature and pressure.