Figure 4.
(A) The porous structure of hydrogels formed by different PH regulators, different γ-PGA contents, and different drying methods [35]. (B) Effect of DOEs on CS/γ-PGA hydrogel [36]. (C) Preparation principle of HA/γ-PGA [41]. (D) HA/γ-PGA hydrogel based on dynamic covalent chemistry, stable covalent chemistry, and IPN strategy [43].