Scientists at OSU are creating transparent sensors on contact lenses that could one day help people living with Type 1 diabetes monitor their blood-glucose levels by transmitting real-time data to smartphones or other devices, such as a wearable pump that can chemically regulate blood sugar.
Tears have all sorts of stuff to tell us. They contain a lot of the same chemicals as your blood, such as glucose—just in lower and more difficult to detect concentrations. Type 1 diabetes, or juvenile diabetes, requires regular blood-glucose monitoring, dietary restrictions, and insulin treatment.
It’s a tough condition to keep up with, but thanks to these advances, patients may soon have important health information sent to their phone in lieu of extracting blood—or at least not as often.
“A lot of Type 1 diabetics don’t wear a pump,” said study corresponding author Greg Herman, a chemical engineering professor at OSU. “Many are still managing with blood droplets on glucose strips, then using self-injection. Even with the contact lenses, someone could still manage their diabetes with self-injection. The sensor could communicate with your phone to warn you if your glucose was high or low.”
The glucose-monitoring contact lenses in combination with a wearable insulin pump could someday even act as a proxy pancreas.
The sensor uses amorphous indium gallium zinc oxide (IGZO) field effect transistors (FETs) to detect minute changes in glucose concentrations in tears. Just a few microns wide,the sensor’s transparent nano-structured network of tightly packed hexagons is created using inexpensive colloidal nanolithography and electrohydrodynamic printing methods which allow for low-cost fabrication. Electrohydrodynamic printing, or e-jet as it is called, is sort of like inkjet printing, but with tiny droplets of biological materials instead of ink. Alright, that’s enough big-kid words for the week in this paragraph alone.
These high-sensitivity sensors could have all sorts of other applications as well.
“What we want to do next is fully develop the communication aspect, and we want to use the entire contact lens as real estate for sensing and communications electronics,” Herman said. “We can integrate an array of sensors into the lens and also test for other things: stress hormones, uric acid, pressure sensing for glaucoma, and things like that. We can monitor many compounds in tears—and since the sensor is transparent, it doesn’t obstruct vision; more real estate is available for sensing on the contact lens.”
The online journal Nanoscale recently published findings from this study, which was conducted by postdoctoral scholar Xiaosong Du, visiting scholar Yajuan Li, and Herman. The study built upon previous research by Herman and other OSU engineers. Similar FET sensors could someday provide a wide range of affordable high-sensitivity insights and solutions to the field of human health.
By Matthew Hunt