Projects per year
We aimed to develop microsensors for eventual glucose monitoring in diabetes, based on fluorescence lifetime changes in glucose/galactose-binding protein (GBP) labelled with the environmentally sensitive fluorophore dye, badan. A mutant of GBP was labelled with badan near the binding site, the protein adsorbed to microparticles of CaCO3 as templates and encapsulated in alternating nano-layers of poly-l-lysine and heparin. We used fluorescence lifetime imaging (FLIM) with two-photon excitation and time-correlated single-photon counting to visualize the lifetime changes in the capsules. Addition of glucose increased the mean lifetime of GBP-badan by a maximum of 2 ns. Analysis of fluorescence decay curves was consistent with two GBP states, a short-lifetime component (0.8 ns), likely representing the open form of the protein with no bound glucose, and a long-lifetime component (3.1 ns) representing the closed form with bound glucose and where the lobes of GBP have closed round the dye creating a more hydrophobic environment. FLIM demonstrated that increasing glucose increased the fractional proportion of the long-lifetime component. We conclude that fluorescence lifetime-based glucose sensing using GBP encapsulated with nano-engineered layer-by-layer films is a glucose monitoring technology suitable for development in diabetes management.
- glucose sensor
1/08/08 → 31/01/12
Saxl, T., Khan, F., Matthews, D. R., Zhi, Z. L., Rolinski, O. J., Ameer-Beg, S., & Pickup, J. C. (2009). Fluorescence lifetime spectroscopy and imaging of nano-engineered glucose sensor microcapsules based on glucose/galactose-binding protein. Biosensors and Bioelectronics, 24(11), 3229-3234. https://doi.org/10.1016/j.bios.2009.04.003