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Researchers at the University of Calgary have released the latest version of their “Wearable Microsystem for Minimally Invasive, Pseudo-Continuous Blood Glucose Monitoring,” a watch-like wearable that “bites” you every few hours to draw blood and test your glucose levels.
The system uses a shape memory alloy actuator which contracts when heated and then snaps back into its original form. “When equipped with a small needle, the SMA-based actuators produced much greater penetration force into the skin than the bioelectric actuators and allowed the team to significantly miniaturize the device,” writes IEEE Spectrum.
“The idea is to have periodic, spontaneous and autonomous biting resulting in reliable blood testing, said researcher Martin Mintchev. “It’s a very significant step in demonstrating autonomous contact with the capillary.”
The system can be used for diabetes management as well as regular genetic testing or any sort of blood analysis that needs to be done regularly. From the paper:
Unlike prevalent solutions which estimate blood glucose levels from interstitial fluids or tears, our design extracts a whole blood sample from a small lanced skin wound using a novel shape memory alloy (SMA)-based microactuator and directly measures the blood glucose level from the sample. In vitro characterization determined that the SMA microactuator produced penetration force of 225 gf, penetration depth of 3.55 mm, and consumed approximately 5.56 mW·h for triggering. The microactuation mechanism was also evaluated by extracting blood samples from the wrist of four human volunteers. A total of 19 out of 23 actuations successfully reached capillary vessels below the wrists producing blood droplets on the surface of the skin. The integrated potentiostat-based glucose sensing circuit of our e-Mosquito device also showed a good linear correlation (R2 = 0.9733) with measurements using standard blood glucose monitoring technology. These proof-of-concept studies demonstrate the feasibility of the e-Mosquito microsystem for autonomous intermittent blood glucose monitoring.
The e-Mosquito isn’t quite ready for prime time but it’s a fascinating move forward for folks who have to check their blood sugar regularly. A quick pinch by a cool watch might just be better than the current prick methods used by diabetics.
