Sugar detection is important for many applications. New developments in sugar signaling would provide new technologies to monitor glucose and other sugars. Azo dye 1 presents a new way to build molecular color sensors for monosaccharides. The boronic acid group is used as chelator group for monosaccharides and linked directly in resonance with the aromatic dye. Dye 1 shows a color change, from orange to purple, in the presence of sugar at neutral pH. [structure: see text]

Diffusional motions of 1,6-diphenyl-1, 3, 5-hexatriene (DPH) were observed by differential polarized phase fluorometry. The measurements indicated that the depolarizing rotations of DPH in propylene glycol are isotropic. The results in vesicles of dimyristoyl-l-alpha-phosphatidylcholine indicated that diffusional rotations of DPH are dominated by hindered torsional motions. Combined use of both differential phase and steady-state anisotropy measurements showed that the average rotational angle of DPH, at times long compared to the fluorescence lifetime, is limited to about 23 degrees at temperatures below the transition temperature of the lipid and that these rotations become less hindered above the transition temperature. The evidence that the depolarizing rotations of DPH in a lipid bilayer are different from those in an isotropic solvent calls into question the meaning of membrane microviscosity as determined by fluorescence anisotropy.