Published in Chemistry World, 19 May 2011
Liquid crystals could one day be used as bio-sensors, detecting the presence of minute amounts of pathogens. That is the claim of a US group of researchers, who have demonstrated how a liquid crystal changes orientation in the presence of bacteria.
Unlike normal materials, liquid crystals have a distinct phase between the solid, ordered crystalline phase and the disordered liquid phase: the liquid-crystal phase. In this phase, the molecules of a liquid crystal try to become ordered. In a nematic liquid crystal like 5CB (4-pentyl-4′-cyanobiphenyl), for example, the molecules try to align lengthways.
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