A rainbow patch that reads your heartbeat
Researchers at the Norwegian University of Science and Technology (NTNU) have built a small transparent patch that looks like the back of a CD and, paired with an ordinary smartphone camera, can measure pulse and blood vessel stiffness. Medical Design & Development, which republished the university’s story on October 30, calls it the first of its kind. The patch is silicone rubber with no electronics or cables.
How it works
One side carries a nanoscale pattern that changes color when the material stretches. The other side has a three-dimensional adhesive structure inspired by octopus suction cups so it grips skin. When pulse waves move the skin, the patch stretches and its color shifts slightly. Any camera, including a phone camera, can detect the change; no spectrometer or laser is required.
Associate professor Angelos Xomalis says the team wanted a flexible, low-cost device whose heart signal can be seen on the patch itself.
Different from a smartwatch
Smartwatches use green LEDs to track blood volume, called optical monitoring, which Xomalis notes is strongly influenced by skin pigment and works less well on dark skin. The patch instead responds to mechanical motion of the skin surface, so it does not depend on how light is absorbed. It can also estimate blood vessel stiffness, which currently needs electrodes on the chest, arms and legs wired to an ECG machine.
Postdoctoral fellow Torjus Lines Steffensen says the approach shifts complexity from the sensor to the smartphone.
Where it could matter
The researchers point to remote areas where specialized staff and equipment are scarce, since a health worker would need little more than a phone. They see it as a possible start of cheap, power-free wearable sensors. The announcement describes a design and test effort at NTNU; it does not report clinical approval or a launch date, so this remains a research prototype.
Practical takeaways
- Watch for clinical validation studies before treating the patch as a diagnostic tool.
- Skin-tone-independent sensing is a useful design goal to look for in future wearables.
- This is news about a prototype, not medical advice or a product you can buy.
Bottom line
NTNU’s patch trades electronics for physics: a color shift read by a camera. If it holds up in clinical testing, it could widen access to basic cardiovascular checks.