Low cost LEDs provide promising light for diabetes.

UK researchers have developed a technique that might literally light the way for the future of diabetes management. Current testing methods involve daily pinprick tests to monitor blood sugar levels but recent advances and techniques could make such tests obsolete with the application of remote fluorescence spectroscopy.

The researchers, led by David Birch, professor of photophysics at Strathclyde University and John Pickup, professor at Kings College London, focused on the intrinsic fluorescence of molecules in the body such as proteins and the molecule NADH, which is essential in the glycolytic pathway leading to the release of energy during metabolism. It was reasoned that the more NADH there was in human tissue, the more glucose there would likely be. With that in mind, the team looked at the fluorescence decay of such species using a newly developed, inexpensive and miniaturized light source. Until recently the only available light sources for exciting ultraviolet fluorescence in tissue were expensive lasers, synchrotrons or spark sources, all impractical in sensors for humans. However, the researchers have now demonstrated the excitation of protein fluorescence using 280nm excitation from a light emitting diode (LED), a step which helps pave the way to the fabrication downstream of lab-on-a-chip glucose sensors. Another LED emitting at 340nm for NADH excitation is now also available. 

Proteins are specific to particular biological functions in the body and thus make useful natural sensors for the role they undertake. The researchers, from both academia and industry, applied this information across scientific disciplines to obtain their results. However, the future holds many challenges, as Colin McGuinness, a postgraduate student in the group, told Chemistry World. 'One problem with this method is the melanin barrier,' he said, 'Melanin in skin absorbs in the UV region inhibiting the intrinsic fluorescence of biomolecules.' The group is currently working to overcome the problem.

The team warns that a commercial device to monitor blood-sugar levels automatically and administer insulin in individual patients accordingly will not be available for some time. However, Birch and colleagues believe that non-invasive glucose sensing is a priority to improve the everyday lives of the millions of diabetics worldwide.

Vikki Allen