Fig. 2.

Morphological characterization of NGCs. (a) (A) Scanning electron microscopy (SEM) image of the cross-section of the self-rolled chitosan tube; (B) its inner surface topography; and (C) photograph showing the whole tube after self-rolling in PBS. (b) (A) SEM image of the cross-section of the chitosan tube coated with eADF4(C16)-RGD on the inner surface (not visible here); (B) of the resulting inner surface topography; and (C) photograph showing the whole tube after self-rolling in PBS. (c) (A) SEM image of a chitosan tube comprising an inner lining with an anisotropic non-woven mat made of eADF4(C16); (B) magnified image of (c) (A) (white box): The chitosan tube and the non-woven mat are physically connected because of the processing conditions. (c) (C) Magnified image of (c) (A) (black box): The eADF4(C16) non-woven nanofibers were deposited on the chitosan inner surface in an anisotropic manner (the white arrow indicates the direction of nanofiber orientation). (c) (D) Photograph showing the whole tube after self-rolling in PBS. (d) (A) Photograph of a collagen cryogel stored in PBS; (B) Bending of the collagen cryogel in PBS resulted in a sharp bending edge indicating its anisotropic character; and (C) PBS removal from a collagen cryogel yielded a significant volume reduction. (e) (A) SEM image of a freeze-dried collagen cryogel and (B) its cross-section in the chitosan tube. (f) (A) Stereo microscopy image of the anisotropic collagen cryogel within a chitosan tube and (B) of its cross-section; (C) photograph of the chitosan tube filled with the anisotropic collagen cryogel. NGCs, nerve guidance conduits; PBS, phosphate buffered saline.