Implantable glucose sensor
Japanese scientists have come up with a way to produce implantable microbeads that glow in response to blood glucose levels. Writing in PNAS, University of Tokyo researcher Hideaki Shibata and his colleagues describe how they have cleverly coupled two boron-containing acidic molecules to a fluorescent chemical group called an anthracene, which consists of a series of 3 linked rings of carbon atoms and sits between the two acid molecules. This chemical configuration allows the fluorescent behaviour of the anthracene to be manipulated by glucose; the more there is present, the brighter the glow emitted when they are illuminated by light of the correct wavelength.
To make the chemicals useable, the team have also developed a way to package them up into tiny microbeads made of a porous and inert substance called polyacrylamide. The researchers were able to safely inject these beads, which measure about 1/100th of a millimetre across, under the skin of a group of experimental mice where they correctly indicated blood glucose levels, including when the levels were altered by injecting insulin or sugars. This approach, say the team, is a step towards producing highly accurate non-invasive monitoring systems enabling diabetics, and even automatic machines, to record blood glucose levels from moment to moment, helping to achieve much better control of blood sugar levels.