Scientists at Draper Laboratory, a research company out of Cambridge, Massachusetts, are developing an injectable nanomaterial that fluoresces under infrared light in the presence of predetermined amounts of glucose. The idea is to make something like a tattoo that can provide constant monitoring for diabetics. So far, investigators at Draper have developed a version that can detect sodium, and are now working to transfer the technology to glucose.
MIT Technology Review reports:
The material consists of 120-nanometer polymer beads coated with a biocompatible material. Within each bead is a fluorescent dye and specialized sensor molecules, designed to detect specific chemicals, such as sodium or glucose.
When injected into the skin, the sensor molecule pulls the target chemical–say, sodium–into the polymer from the interstitial fluid, which surrounds cells. To compensate for the newly acquired positive charge of a sodium ion, a dye molecule releases a positive ion, making the molecule fluoresce. The level of fluorescence increases with the concentration of the chemical target. Scientists can swap in different recognition molecules to measure different targets, including chloride, calcium, and glucose. The range of concentrations that the sensor can detect can be varied by altering the ratio of the components, depending on whether it is important to measure precise concentrations or more broad variability.
The sodium sensor, which could one day be used to monitor dehydration, has shown early success in animals. When injected into rodents’ skin, the beads stay put and fluoresce in response to saline injections. The researchers have developed a glucose sensor that works via a similar mechanism. It has been shown to work in a solution but has not yet been tested in animals.
Video of cells injected with the new material fluorescing in the presence of sodium:
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