New Liquid Crystal Sensor Detects Spoiled Foods!

There’s got to be a less offensive way to sniff out spoiled food than using your nose, right? Well now there is thanks to University of Wisconsin researcher Nicholas Abbot, who, along with Rahul R. Shah of the 3M Corporation, has created a sophisticated sensor small enough to be worn as a badge that is capable of detecting environmental hazards ranging from toxic chemicals to spoiled foods.

The device, still in the R&D stage, consists of an ultrathin gold film with nonscale corrugation. The surface of the gold film is dotted with protruding chemical receptors that weakly anchor liquid crystal in a well-defined orientation along the film’s surface. When these receptors are exposed to the specific chemical that is the object of detection, however, they bond more strongly with that target chemical than they do with the liquid crystal. The new orientation is visible to the naked eye as a change in the sensor’s color or brightness.

Food safety applications would include monitoring for levels of the compounds produced by rotting fish and meat—levels down to parts-per-billion of vapor concentrations in the air. It could also be used to detect environmental exposure to pesticides, as well as deadly nerve gas.

Sure beats poking your snout into a package of week-old chicken....