A patch that can detect even minute amounts of sweat in real-time, inspired by the legs of frogs, has been released.
A research team led by Professors Bang Chang-hyeon and Cho Soo-yeon from Sungkyunkwan University has developed a soft, lightweight optical adhesive biosensor patch that mimics the frog's foot.
Biosensors for bioadhesion are gaining attention as a technology for real-time early diagnosis of various diseases. However, there are challenges in rapidly collecting and analyzing fluids from the biological surface. Existing sensor systems cannot collect and analyze the minute amounts of fluid that are secreted at unpredictable intervals in real-time. Only equipment that forcibly extracts and analyzes bodily fluids is available.
The research team focused on the footpads of amphibians like frogs. The frog's footpad has hexagonal adhesive parts and a microscopic drainage structure. The team applied this structure from the frog's footpad to the patch to quickly expel bodily fluids and ensure a tight adhesion to curved biological surfaces.
Inside the sensor, a hydrogel with excellent moisture absorption is combined with a near-infrared band luminescent single-walled carbon nanotube sensor that is biocompatible. It has a structure that can effectively absorb even small amounts of fluids such as sweat or hormones.
The patch developed by the research team was able to quickly detect minute amounts of sweat at the level of 75 nanoliters (one billionth of a liter) in real-time within 45 seconds, even without movement or external stimuli. This enabled the simultaneous analysis of various molecules that indicate vitamin content or stress levels in bodily fluids.
The research team noted, "The biosensor technology developed this time can evolve into ultra-compact precision biosignal monitoring technology combined with various optical sensors and is expected to extend to wearable healthcare, micro-life phenomenon analysis, and precision medicine fields."
References
Nature Communications (2025), DOI: https://doi.org/10.1038/s41467-025-58425-x