Figure 4.

(A) Engineering a nanofiber-hydrogel composite with interfacial bonding between the fiber surface and hydrogel network. Left column: Schematic of the synthesis and structure of the PCL nanofiber-HA hydrogel composite (NHC). Right column: SEM images of the NHC (left) and porcine native spinal cord ECM (right), and the oscillatory strain sweep tests of the HA hydrogel and composites with and without interfacial bonding. (B) The NHC limits the collapse of the contused spinal cord and facilitates tissue formation in the injury. (C) Upper panel: The NHC stimulated neurogenesis in the injury. Microphotographs showing immature neurons stained with antibodies against βIII-tubulin and around the injury in representative horizontal sections of each treatment group at 3 (a), 7 (b), and 28 (c) days post-injury (dpi) and a representative area for each group at 28 dpi shown in high magnification. Bottom panel: Bar graph showing the average density of immature neurons per mm² in the injury for each experimental group at 3, 7, and 28 dpi, and the microphotographs showing neural precursor cells stained with antibodies against doublecortin (DCX, red) in and around the injury in horizontal sections of each treatment group at 28 dpi. Adapted with permission from ¹¹², Copyright 2020 Elsevier.