Experts design tiny beads to monitor blood sugar

Researchers in Japan have designed tiny beads that detected blood sugar levels when implanted in the ears of mice and they hope to eventually use this to replace more invasive techniques in people with diabetes.

Laced with diboronic acid and certain hydrocarbons, the beads glow when they pick up glucose floating in the blood, the scientists reported in the journal Proceedings of the National Academy of Sciences on Tuesday.

"Due to the virtue of their small size, the fluorescent microbeads are injectable, minimally invasive and rapidly respond to glucose change," wrote the researchers, led by Shoji Takeuchi at the University of Tokyo's Life Bio Electromechanical Autonomous Nano Systems Center.

The beads are smaller than the inner diameter of a general injection needle and the mice did not display abnormal behaviour after the beads were injected just under the skin of their ears.

In the experiment, the scientists found that the intensity of the glow from the beads mirrored closely sugar levels measured directly from blood samples taken from the mice.

"Because the fluorescent microbeads do not require external links or power sources to provide a readout, they could be used to fabricate minimally invasive glucose sensors for people who need to continuously monitor their blood glucose levels," they wrote.

Diabetes happens when the pancreas produces too little or no insulin, leaving the body unable to regulate blood sugar. Left untreated, the person risks heart disease, kidney failure, nerve and blood vessel damage, blindness and other complications.

For decades, diabetics have monitored their blood sugar using conventional instruments, which require them to prick their fingers and draw blood, up to several times a day.

According to the World Health Organisation, more than 220 million people worldwide suffer from diabetes and 1.1 million people died from the disease in 2005. This death figure will more than double by 2030.

SOURCE: Proceedings of the National Academy of Sciences, online October 5, 2010.