Injectable Glucose Sensor Component Costs One-Tenth as Much

Continuous glucose monitors give millions of people with diabetes a real-time view of their glucose levels, helping them make decisions about medication, diet, and daily activities. Yet these devices remain out of reach for some patients because of their cost. Researchers at Texas A&M University have taken a step toward solving that problem by identifying a lower-cost component for an experimental injectable glucose sensor. The new sensing material costs roughly one-tenth as much as a commonly used alternative while delivering similar performance.

Many glucose-monitoring systems depend on enzymes to detect glucose. The approach developed by the research team works without enzymes, using near-infrared fluorescence instead, so changes in glucose levels can be tracked through changes in a light signal. The system relies on a process called competitive binding. A protein known as concanavalin A has binding sites that can hold either glucose or a fluorescent sugar compound. As glucose levels rise, glucose molecules take over more of those sites and push out the fluorescent compound, which changes the fluorescent signal and reveals how much glucose is present.

Earlier versions of the technology used a relatively expensive compound called alpha-mannopentaose as the fluorescent sugar. The researchers compared several glucose-binding compounds and found that beta-mannopentaose, a far cheaper material, provided comparable sensing performance. It also worked well in artificial interstitial fluid, a solution designed to mimic the environment beneath the skin. The researchers were surprised by how closely the lower-cost material matched the more expensive one, noting that the cheaper option was not really a compromise.

To turn the chemistry into a usable sensor, the team placed it inside a small hydrogel that can be injected into tissue and is designed to sit beneath the skin. The gel serves as a stable home for the sensing materials while still allowing glucose to pass through and be measured. In testing, the hydrogel held on to more than 94 percent of the sensing materials over seven days, showing that the lower-cost chemistry can function within an injectable platform.

The researchers emphasize that the technology is still at the proof-of-concept stage and will need further development and testing before it could be considered for clinical use. They plan to keep refining the platform and to evaluate additional components that could improve its performance, longevity, and practicality. Their long-term goal is a reliable, affordable injectable glucose sensor that expands access to continuous glucose monitoring, particularly for people in under-resourced communities and those without adequate insurance coverage.