Preparation And Properties Of Medical Self-healing Hydrogel Dressings

Wound dressing is material used to cover ulcer or other damage.With the development of medical,the traditional wound dressing already can’t meet the demand of clinical because of causing tissue adhesion,bacterial infections and single function.Self-healing hydrogel is a new kind of wound dressing developed in recent years,has humid,biocompatibility,wound exudate absorption capability and low wound tissue adhesion.With certain drug loaded in,the antibacterial ability are promoted.This paper aimed to prepare a biodegradable medical self-healing hydrogel dressing for drug delivery and wound healing.First,the gellan gum（GG）is modified by the strong oxidation property of sodium periodate and the oxidized gellan gum（OG）is obtained,then the calcium ions in calcium chloride are ionically crosslinked with OG,and the ionic crosslinked OG is subjected to Schiff-based crosslinking reaction with carboxymethyl chitosan（CMCS）to obtain a double crosslinked hydrogel.At the same time,calcium chloride is used as a cross-linking agent to prepare gellan gum microspheres（GMs）by emulsification cross-linking method.In order to improve the antibacterial property,drug sustained release ability and mechanical properties of the hydrogel,microspheres loaded with antibacterial drugs are encapsulated in it and obtain a composite hydrogel.In the experiment,the effects of the material ratio on the hydrogel,different drugs on the microspheres and the addition of the microspheres on the properties of the composite hydrogel are investigated respectively,and the cumulative drug release antibacterial and self-healing ability of the optimal composite hydrogel scaffold are further evaluated.The results show that:（1）The hydrogel with CMCS:OG=2:1 shows the most excellent mechanical properties,and has a suitable gel time,good swelling performance,and degradation stability.（2）The microspheres with GG:Ca Cl₂=2:1 have uniform particle size,good dispersion,and basically smooth surface morphology.Three different drugs:BSA,TH and Ag SD,have an impact on the properties of the microspheres.（3）The composite hydrogel with a microsphere concentration of 8 mg/m L not only improved the mechanical properties,but also realized the sustained release of BSA,TH,Ag SD within 14 days,and has excellent performance in antibacterial experiments.In summary,this composite hydrogel has great application potential in wound treatment,inhibiting bacterial infections and promoting wound regeneration.