Called Chem-Phys patch, the device records electrocardiogram heart signals and tracks levels of lactate, a biochemical that is a marker of physical effort, in real time, sending data wirelessly to a smartphone, smart watch or laptop via Bluetooth Low Energy. According to the team, the patch could have applications ranging from athletes monitoring their workouts to physicians monitoring patients with heart disease.
“One of the overarching goals of our research is to build a wearable ‘tricorder like’ device that can measure simultaneously a suite of chemical, physical and electrophysiological signals continuously throughout the day,” said Professor Patrick Mercier. “This research represents an important first step to show this may be possible.”
The researchers used screen printing to manufacture the patch on a thin, flexible polyester sheet that can be applied directly to the skin. The lactate sensing electrode is in the centre of the patch, with two EKG electrodes either side. Several iterations of the patch showed the optimal electrode spacing was 4cm.
Researchers also had to make sure the EKG sensors were isolated from the lactate sensor, which works by applying a small voltage and measuring electric current across its electrodes. This current can pass through sweat, which is slightly conductive, and can potentially disrupt EKG measurements. So the team added a printed layer of silicone rubber to the patch and configured it to keep sweat away from the EKG electrodes, but not the lactate sensor.
The team is now working on improving the way the patch and the board are connected, as well as adding sensors for other chemical markers.
