Noninvasive Transdermal Glucose Sensing

Noninvasive glucose measurements can potentially be performed with phase-modulation fluorometry. The blood gas application described above requires drawing the blood, i.e., an invasive as well as an unpleasant procedure. Similarly, present measurements of blood glucose also require fresh blood. Insulin-dependent diabetics 

Present status Invasive, i.e., requires withdrawing of blood Infrequent measurements result in blood glucose variations Long-term health consequences result from inadequate control of blood sugar 

Noninvasive optical measurement of Does not require withdrawing of blood 

What mechanisms can be used to create a lifetime-based glucose sensor In our opinion, the mechanism should be fluorescence resonance energy transfer (FRET). The phenomenon of FRET results in transfer of the excitation from a donor fluorophore to an acceptor chromophore, which need not itself be fluorescent. FRET is a through-space interactor which occurs over distances of 20-60 A. 

The characteristic distances for FRET can be reliably calculated from the spectral properties of the donor (D) and acceptor (A). Importantly, FRET can be reliably predicted to occur for any D-Apair, so that the system can be wavelength-adjusted to match the wavelengths of laser diode sources. The extent of FRET depends on the proximity of the donor and acceptor. 

---