Beneath the skin, a small hydrogel could one day help track blood sugar—and a Texas A&M team has found a way to make one part of its sensing chemistry about 10 times less expensive without giving up much performance.
Continuous glucose monitors give people with diabetes a real-time view of changing glucose levels. That information can help guide choices about medication, food and daily activities. Yet cost can put these devices beyond the reach of some patients. The Texas A&M University study, published in ACS Measurement Science Au, looks at one possible way to bring down the cost of a future injectable monitor. The technology is still at the proof-of-concept stage, not ready for clinical use.
The experimental sensor uses fluorescent molecules to detect glucose without relying on enzymes. Instead, it uses near-infrared light, which lets researchers follow changes in glucose through changes in a light signal. The chemistry depends on a protein called concanavalin A, or ConA, which has binding sites for sugar compounds.
When glucose levels rise, glucose molecules compete with a fluorescent sugar compound for those sites on ConA. As glucose takes up more sites, it displaces some of the fluorescent molecules. The resulting change in light gives the sensor a way to measure glucose concentration.
The team compared several compounds used in this sensing process. It found that β-mannopentaose performed comparably to α-mannopentaose, a compound used in earlier versions of the technology, while costing roughly one-tenth as much. The less expensive material also worked well in artificial interstitial fluid, a solution made to mimic the environment beneath the skin.
“The surprising part was how closely the lower-cost material matched the performance of the more expensive alternative,” said lead author Dr. Sayantan Tripathy, an assistant research scientist in Texas A&M’s Optical and Bio-Sensing Laboratory. “In this case, the cheaper option wasn’t really a compromise.”
Researchers placed the sensing chemistry inside a small hydrogel designed to be injected into tissue and remain under the skin. The gel provides a home for the sensing materials while still allowing glucose to reach them. In tests, it retained more than 94% of the sensing assay—the materials used to produce the measurement—over seven days.
The result matters because the price of a medical device can depend on its individual ingredients as well as how they work together. Study principal investigator Dr. Gérard L. Coté, a biomedical engineering professor, said the findings offer a promising basis for further development. Co-author Dr. Melissa Grunlan said the goal is to make sensors that are both effective and affordable for the people who need them.
There is still a long road between a promising laboratory result and a device patients can use. The researchers say the injectable sensor needs more development and testing before it could be considered for clinical use. For now, the study offers a clear next step: test whether the lower-cost ingredient can help make a future under-skin glucose monitor more affordable while preserving its ability to measure glucose.