K. Kuwata et al., COMPARATIVE H-1-NMR STUDIES ON THE PHYSICAL STATE OF WATER IN SOFT CONTACT-LENS AND MOUSE LENS, Biochimica et biophysica acta (G). General subjects, 1289(3), 1996, pp. 369-376
The physical state of water in mouse lenses (2-, 4- or 8-wk-old) and s
oft contact lenses (SCLs, water content from 18.4 to 79.2%) were studi
ed by measuring spin-lattice relaxation times (T-1) and apparent inter
molecular cross-relaxation times (T-IS) from irradiated protein or pol
ymer protons to water protons, using 360 MHz H-1-NMR spectrometer at 2
5 degrees C. (1) 1/T-1 values of SCLs increased gradually with increas
ing dry weight (W(%)). 1/T-IS values of SCLs were approximately zero a
t W of 20.8 and 26.8%, increased gradually from 26.8% and then steeply
above similar to 50%. (2) A plot of 1/T-1 vs. W(%) of mouse lenses wa
s almost equal to that of SCLs. However, a plot of 1/T-IS vs. W(%) was
an approximately straight line with the intercept at W of 23% and wit
h the slope which is almost equal to that of SCLs above W of similar t
o 50%. The plot of 1/T-IS vs. W(%) of mouse lenses might indicate the
significant change in the physical state of water and/or protein-water
interactions above W of 23%.