OBSERVATION OF REORIENTATIONALLY HINDERED WATER IN BIOLOGICAL TISSUE USING TRIPLE QUANTUM FILTERED O-17-NMR

Water dynamics in aqueous biopolymer solutions often display a two-pha se character, resembling water-water and water-protein interactions. R otationally hindered water molecules in crowded protein environments d isplay triple exponential magnetic relaxation out of the extreme narro wing limit. Because water-protein interactions retard the water dynami cs, (H2O)-O-17 magnetization passes through a NMR multiple quantum coh erence filter, allowing the visualization of reorientationally hindere d water without the disturbing resonance of the bulk. In vitro experim ents performed on selected biological materials (lens, vitreous body a nd serum albumin solutions) clearly demonstrate the potential of this technique.