UC San Diego sensor pen

The key to wearable Health Tech devices is to have inexpensive sensors that can collect the desired biometric data. The problem is that these can be expensive or complicated to use. So how about sensors that you can just draw on your skin where you need one? It sounds crazy, but that’s what researchers at University of California San Diego have done.

We’ve covered projects from UC San Diego in the past, such as their glucose-measuring tattoo or their sweat-powered battery. In this program, they have created an ink based on polyethylene gycol with graphite powder to create an electrical conductor. They then add enzymes that will change their conductivity in the presence of a target chemical compound. They loaded this ink into standard, off-the-shelf ballpoint pens, and were able to draw sensors wherever they wanted.

For example, an enzyme that detects glucose can be used to create a sensor that measures glucose levels in a subject’s blood. They drew the sensor on a flexible substrate and then applied a drop of blood obtained from a finger stick, but it is conceivable that a similar approach could be used to draw a sensor directly on a subject’s skin. Other enzymes can be used to detect pollutants in the air or pesticides. The researchers estimate that you can draw as many as 500 sensors from a single pen. As a result, we may soon have a convenient way to measure just about anything on our bodies just by writing on our skin.