University of Florida engineers have designed and tested versions of a sensor that can diagnose and treat a variety of diseases, for example, by monitoring diabetics' glucose levels via their breath or detecting possible indicators of breast cancer in saliva. The sensor can be mass-produced inexpensively with technology currently used for making chips in cell phones.

In the study, the sensor was integrated in a wireless system that detected glucose in exhaled breath and delivered the data to healthcare workers. Although glucose levels found in exhaled breath were once thought to be too small to provide accurate measurements, this sensor uses a semiconductor to amplify the minute signals to readable levels.

The sensor works by mating different reactive substances with the semiconductor gallium nitride, said Fan Ren, a professor of chemical engineering and a collaborator on the project. For instance, if it is programmed to detect cancer, the substance is an antibody that is sensitive to certain proteins identified as indicative of cancer. If the target is glucose, the reactive molecules are composed of zinc oxide nanorods that bind with glucose enzymes. When a reaction occurs, "the charge on the semiconductor devices changes, and we can detect that change," Ren said.

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