A pair of researchers at Korea University have turned to an unusual material to create low-cost medical sensors: Tootsie Roll candies, now a tasty lickable sensor for ovulation status or kidney health.
"Soft candy was discovered to be an excellent electronic material and was used to fabricate electrodes for salivary conductivity-based diagnostics," the researchers write of their project. "Using a simple molding process, a soft candy (Tootsie Roll) was made into 20 × 20 × 5 mm electrodes with a stable frequency response (0.1–100 kHz)."
Building on an earlier idea to use the salt and electrolyte levels of a person's saliva to track everything from ovulation cycles to kidney health, the researchers looked fro a low-cost and widely-available material from which a lickable sensor could be made — and found the perfect solution in the form of Tootsie Rolls.
The sensors were constructed using a flattened Tootsie Roll into which a cross-hatch pattern was pressed, as a means of holding a sample of saliva. Two thin aluminum tubes provide electrical connectivity to a simple voltage detector circuit — which, in turn, provided a means of measuring the levels of salt and electrolytes in the saliva. When you're done, the sensor can be easily disposed of — by removing the electrodes and popping it in your mouth as a tasty snack.
"[The sensor] is suitable for monitoring the ovulation cycle for natural family planning as well as chronic kidney disease diagnosis," the researchers discovered. "Given the ubiquity of soft candy, the simplicity of the molding process, and the negligible medical waste stream, it is a more appropriate approach to diagnostics design for resource-scarce clinical settings, such as those in developing countries.
"The broader impact of this work will be the paradigm shift of soft candy from food to a new class of edible, moldable, high-resistivity, and stable electronic materials."
The pair's work has been published in the journal ACS Applied Materials & Interfaces under closed-access terms.