Fig. 7. SEM images of silk 3D hydrogels fabricated by different methods. (A) Electro-gelation (particulate structure). Reprinted with permission from ref. 60 Copyright © 2011 Elsevier. (B) Freeze drying (lamellar structure). Reprinted with permission from ref. 61 Copyright © 2012 Elsevier. (C) Chemical crosslinking (micro porous). Reprinted with permission from ref. 62 Copyright © 2020 American Chemical Society.
