Preparation Of Conductive Cellulose Nanocrestal Doped Gelatin Hydrogeland Its Application For Skin Wound Repair

Gelatin is a hydrolysate of collagen,which has good biocompatibility and low immunogenicity for in vivo application.Gelatin-based hydrogels have been widely used in the field of biomedical engineering.However,pure gelatin-based hydrogels show weak mechanical strength,non-conductivity,and poor thermal stability,and therefore cannot be used for long-term implantation.Poly 3,4-ethylenedioxythiophene(PEDOT)with high conductivity is an excellent candidate to be used as conductive filler for constructing conductive hydrogel.However,bare PEDOT has poor water dispersibility,which limits its combination with the hydrophilic hydrogel network.In this study,we firstly prepared PEDOT-coated conductive cellulose nanocrystals(CCNs)by employing polydopamine(PDA)as the bridging unit.Due to its adhesiveness,PDA enabled in situ polymerization of 3,4-ethylenedioxythiophene(EDOT)on cellulose nanocrystals(CNC).Secondly,we designed gelatin-based hydrogels(DNHs)with an interpenetrating double network structure.The first flexible network was formed by cross-linking gelatin with polyethylene glycol diglycidyl ether(PEGDE),and the second rigid network was self-crosslinked by polyethylene glycol diacrylate(PEGDA).Compared with single network gelatin-based hydrogels(SNHs),the DNHs hydrogels have improved mechanical performances.Then,CCNs were incorporated into DNHs hydrogels to prepare conductive CCNs-gelatin-based hydrogels(CDNHs).The CDNHs have good mechanical properties,high conductivity,repeatable temperature-sensitive adhesion,and biodegradability.In vitro cell culture experiments proved that the CDNHs hydrogel facilitated the adhesion and spreading of L929 fibroblasts;Rat full-thickness skin defect experiments demonstrated that the CDNHs hydrogel enhanced skin repair,compared with the blank group.In summary,this study prepared conductive cellulose nanocrystals with good electrical conductivity and water dispersibility based on the mussel-like adhesion chemistry.Based on the interpenetrating double network enhancement mechanism,this study prepared double-layered cellulose with good mechanical properties and thermal stability.Hydrogel network And the prepared conductive cellulose nanocrystals were incorporated into the gelatin-based double-network hydrogels to obtain conductive gelatin-based hydrogels.The as-prepared hydrogels showed good conductivity,temperature-sensitive adhesion,degradability,and biocompatibility,which will have great potential in applications of electrophysiology,biosensors,tissue engineering and other fields.