Glucose-Monitoring Hydrogel Sensor Changes Color When Glucose Levels Rise
University of Illinois engineers have developed a new continuous glucose monitoring material that changes color as glucose levels fluctuate, and the wavelength shift is so precise that doctors and patients may be able to use it for automatic insulin dosing – something not possible using current point measurements like test strips. The new sensor is made of hydrogel, a soft elastic jelly-like material, laced with boronic acid compounds. Boronic acid binds to glucose, causing the gel to swell and expand as the glucose concentration rises. Embedded within the hydrogel is a photonic crystal made of tiny, carefully arranged beads. A photonic crystal only reflects one wavelength of light while the rest of the spectrum passes through. As the hydrogel expands, the reflected color shifts from blue to green to red.