Self-healing Silk Colloidal Hydrogels For Tissue Engineering

Tissue engineering applies the principles of engineering and life sciences to the development of alternatives to biological tissues to restore,maintain or improve the function of tissues,and biomaterials are at the heart of tissue engineering and need to have good biocompatibility and low immune properties in vivo.With the improvement of medical standards,it is also hoped that the material will have an appropriate degradation rate and that the degradation products can be absorbed by the human body to avoid the harm of secondary surgery to patients.Compared with inert materials and synthetic polymers,the advantages of natural biological materials are increasingly concerned by researchers,among which silk protein materials have great potential for tissue engineering materials.In this research work,a silk-based colloidal gel was prepared,through the colloidal gel a bottom-up assembly method,and discontinuous silk nanounits assembled into a tissue engineering material with both fine microstructure and stable macrostructure,reversible interaction gives the material shear thinning and self-healing properties,the colloidal gel material is completely composed of natural polymers,without the introduction of inorganic components and synthetic polymers can have strong mechanical properties.The main research content of this article is divided into the following three parts.The first part is the preparation and characterization of silk fibroin nanoparticles: the basic unit of colloidal gel is obtained by processing natural silk fibroin cocoons,and the molecular weight of the regenerated silk fibroin solution is regulated by changing the system,which is characterized by GPC technology.The properties of silk fibroin nanoparticles were controlled by changing different molecular weight,concentration of regeneration solution,and antisolvent method.The size of silk fibroin nanoparticles was characterized by SEM and DLS.The formation process of colloidal particles was characterized,and the dominant mechanism of colloidal particle self-assembly was explored through rheological data.In the second part,the macroscopic characterization of the silk fibroin-based colloidal gel was carried out.Combined with the mechanical properties of the material,the correlation between the concentration of the dispersed phase in the colloidal system and the gel properties was analyzed,which proved the good formability and Shear thinning self-healing properties.In order to further improve the stability of the gel material,the idea of combining silk fibroin colloid gel with crosslinking-modification was proposed for the first time to prepare a secondary curable silk fibroin particle gel,which can be used for a long time under physiological environment.keep it steady.The last part proposes a colloidal gel composed of granular materials composed of silk fibroin and gelatin.The composite components in the particles stabilize the particles through the β-fold formed by the silk fibroin components,avoiding toxic cross-linking agents.With the addition of MSCs,the cytocompatibility of the gel material was tested by using mesenchymal stem cells,and the cells had good biocompatibility and proliferated and spread on the scaffold.