Injectable, Grain-of-Rice-Sized Glucose Biosensor Continuously Measures Sugar Levels

The first glucose self-monitoring system, developed in 1970, was a bulky device weighing three pounds and requiring a substantial blood sample, primarily intended for use in physicians' offices. Since then, continuous glucose monitors (CGMs) have evolved significantly, but even modern versions can be cumbersome and their maintenance may discourage users. To overcome these limitations, researchers are now developing a fully injectable CGM, as small as a grain of rice, which can be paired with an external optical reader to measure sugar levels at any time.

A research team at Texas A&M Engineering (College Station, TX, USA) has secured a grant from the National Science Foundation (NSF) to work on this innovative project. The aim is to create a minimally invasive, injectable glucose biosensor and a corresponding wearable device. The sensor, once injected under the skin, is designed to work with a watch-like reader that uses light to determine glucose levels. This reader then transmits the data to a smartphone, allowing the user to easily share information with their healthcare provider.

In addition to the sensor’s unique size and injectability, the optical sensing technology used in the sensor and wearable reader is particularly suited for individuals with darker skin tones, a demographic that has faced challenges with biosensing technologies. The researchers are currently enhancing the sensor's biocompatibility by enclosing its sensing chemistry within a thermoresponsive membrane. This specialized membrane is designed to subtly adapt within the body, swelling and shrinking just enough to prevent cell and protein adhesion, thereby reducing the likelihood of scar tissue formation around the sensor. The team has already patented this membrane technology and is exploring its potential applications in various medical devices, aiming to extend their functional lifespan.

“The membrane could be applied to assorted devices that are prone to adhesion processes in the body,” said co-principal investigator Dr. Melissa Grunlan. “It could be used on maybe a catheter to prevent thrombosis and infection by preventing the accumulation of proteins, cells, and organisms.”

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