Structural characterization of channel cavities with micrometer-scale diameters in highly-oriented polypeptide gels by three-dimensional NMR imaging and diffusion NMR methods

Highly-oriented poly(γ-benzyl l-glutamate) (PBLG) gels prepared by cross-linking PBLG chains by changing the concentration of ethylenediamine as cross-linker in 1,4-dioxane in the presence of the strong magnetic field of an NMR magnet with a strength of 10.5 T have been structural-characterized by three-dimensional (3D) NMR imaging and diffusion NMR. From these experimental results, it is shown that long channel cavities with μm-scale diameters in the polypeptides are formed along the direction parallel to the α-helical axis. Further, diffusion behavior of solvent in the polypeptide gels has been elucidated as associated with channel cavities by diffusion NMR.