Prototype could signal end to invasive blood tests
Diabetes sufferers often have to prick themselves several times a day to check their blood glucose levels, but it could soon be possible for the same measurements to be taken non-invasively via a contact lens.
Researchers at the University of Washington have developed a prototype system based on a lens that can measure glucose levels in tear fluid and relay them wirelessly to a monitor. Medical research has already established a correlation between tears and blood as glucose-level indicators.
A glucose sensor is mounted with three metal layers on a lens upon a transparent polyethylene terephthalate (PET) substrate compatible with the lens. A coil that avoids the corneal area then connects this to a readout IC and the entire system is powered wirelessly by incoming 2.4GHz power.
The sensing area is 0.22sq mm and the sensor chip is 0.5x0.5sq mm to allow for the radius of curvature of the human eye.
“The small chip area, high level of integration and low power of our system allows application in multiple bio-sensing tasks, including smart contact lenses,” the researchers said.
The University of Washington’s work was presented at this week’s International Solid State Circuits Conference in San Francisco, which has taken ‘Electronics for Healthy Living’ as its main theme.