fig3

Figure 3. Design of hydrogel networks and microstructures. (A) Schematic illustration for the hydrogel fabrication by freezing a polymer solution on a copper substrate; (B) SEM images of the freeze-casted and annealed (FC-A) PVA hydrogels. (A and B) are reprinted with permission from Ref.^[69]. Copyright 2021, Wiley-VCH; (C) Fabrication process: (i) 3D Printing, (ii) Mechanical Training, (iii) Electrochemical Training^[74]. Copyright 2026, Wiley-VCH; (D) Preparation of biomimetic chitin-protein OfCPH-2 (BM)-hydrogel^[76]. Copyright 2025, Wiley-VCH; (E) Schematic illustration of the fabrication of CSP-LB hydrogel^[49]. Copyright 2023, Wiley-VCH. SEM: Scanning electron microscopy; PVA: poly(vinyl alcohol); BM: biomimetic chitin-protein OfCPH-2; CSP-LB: chitosan/silk fibroin (CS) hydrogels loaded with platelet-derived growth factor-BB (PDGF-BB) to construct a smart injectable thermo-responsive hydroge; HFIP: hexafluoroisopropanol; LDHs: layered double hydroxides; BMP-2: bone morphogenetic protein 2; PDGF-BB: platelet-derived growth factor-BB.