Korea University professors Beelee Chua and Donghyun Lee have developed a health monitoring sensor using saliva collected from a Tootsie Roll candy to detects salt and electrolyte levels, and monitor ovulation status and kidney health.
The easily accessible, low-waste sensor is simply licked.
To make the prototype sensor, a Tootsie roll was flattened and crevices were pressed into its surface to hold the saliva sample. Two thin, reusable aluminum tubes were inserted, acting as electrical contacts, connecting the candy electrode into a circuit with a current source and an output voltage detector. In preliminary tests, the device could measure salt levels that were physiologically relevant for health monitoring in a salt-water solution and artificial saliva. When covered in diluted artificial saliva, the sensor could reliably measure a change in voltage low enough to detect the 10 to 30 percent drop in salts that occurs when a person ovulates. While the maximum salt content in the artificial saliva samples was similar to that of a healthy adult, the researchers used calculations to estimate that conductivities three times higher, which signal a problem with the kidneys, would be within the measurable range of the device.