Erratum to: Integrated printed BDNF/collagen/chitosan scaffolds with low temperature extrusion 3D printer accelerated neural regeneration after spinal cord injury

doi: 10.1093/rb/rbab047, Regenerative Biomaterials 2021;1–20

In the originally published version of this manuscript, the supplementary figures were omitted. The supplementary figures are now available online.

Fig. S1. Schematic illustration of the experimental procedure.

Fig. S2. In vivo degradation curves of 3D-CC-BDNF scaffolds with five mass ratios.

Fig. S3. The image of DCX (green) immunofluorescence staining. Immature neurons were identified by immunostaining with anti-DCX antibody (green) (A) at 7 days after co-culture. Dapi antibody (blue) was performed to counter-stain cell nuclei (A) at 7 days after co-culture. Quantification of the DCX+ cell density (B) and the ratio of DCX+/Dapi (C). Data were presented as mean ± SD, n = 5. *P < 0.05 vs 3D-CC+BDNF. ##P < 0.01 vs 3D-CC. Scale bars = 50 µm in panels (A).

Fig. S4. Biocompatibility testing of scaffolds and human umbilical cord mesenchymal stem cells in vitro. (A) Typical cell morphology of the fourth generation HUCMSCs under a phase contrast microscopy. (B) Expression of CD90, CD105, CD73 and negative molecules (Neg PE) (CD45, CD116, CD19 and HLA-DR). (C-D) Double immunostaining with anti-CD90 antibody (green) and anti-CD105 antibody (red) to identify HUCMSCs. D was an amplified image of the yellow box in C. (E-F) Morphological observation of HUCMSCs cultured on 3D-CC+BDNF (E) and 3D-CC-BDNF (F) under a phase contrast microscope. The image on the right was an amplified image of the yellow box in the image on the left. (G-H) Scanning electron microscopy observation of HUCMSCs growth status in 3D-CC+BDNF (G) and 3D-CC-BDNF (H). (I-J) Double immunostaining with an anti-CD90 antibody (green) and an anti-CD105 antibody (red) to identify HUCMSCs in the 3D-CC+BDNF (I) and 3D-CC-BDNF (J). (K-L) HE staining observation of 3D-CC+BDNF (K) and 3D-CC-BDNF (L) co-cultured with HUCMSCs. (M) Light absorbance of HUCMSCs in the 3D-CC+BDNF and 3D-CC-BDNF co-cultured with HUCMSCs at 1, 3, 5 and 7 days after seeding HUCMSCs. Data were presented as mean ± SD, n = 5. *P < 0.05, **P < 0.01 vs 3D-CC+BDNF. Scale bars = 50 µm in panels (A, C, D, E, F, G, H, K, L), 300 µm in panels (I, J).