Autonomic Self Healing Silk Fibroin Injectable Hydrogels Formed via Surfactant Free Hydrophobic Association.
Many natural materials, such as silk, animal bone, nacre, and plant fibers, achieve outstanding strength and toughness through the rupture of sacrificial bonds between chain segments in the organic phase. In this work, we presented a bioinspired strategy to fabricate silk fibroin based hydrophobic interaction (HA) hydrogels by incorporating the hydrophobic interaction as sacrificial bond into the alginate ionic network that not only enhanced mechanical extensibility, strength, and toughness of the hydrogels, but also enabled self recovery and self healing properties via reversible hydrophobic interaction without external stimuli at room temperature. The hydrophobic interaction system consisted of hydrophobic monomers stearyl methacrylate (C18M) and amphiphilic regenerated silk fibroin (RSF) solution. The mechanical tests and rheometry indicated that the hydrophobic interaction served as sacrificial bond that preferentially rupture prior to the alginate ionic network under external load, which dissipated enormous amounts of energy and conferred improved mechanical performance. Moreover, the structure of HA gels could be quickly recovered after injection due to the existence of hydrophobic interaction. In addition, the degradability of the HA gels in a protease XIV solution was strongly dependent upon the C18M component, which significantly promoted the degradation rate of HA gels. The biomimetic mineralization process of HA gels within simulated body fluid (SBF) mimicking the inorganic composition of human blood plasma, was performed and the calcium phosphate nanoparticles on the hydrogel were observed. Importantly, in vivo experiments illustrated that the HA gels exhibited satisfying biocompatibility, and the mouse osteoblasts (MC3T3 E1) could attach and spread on the hydrogels. Overall, the HA gels with self healing, biocompatibility and high mechanical properties provided it potentially suitable for load bearing applications in tissue engineering, such as in cartilage replacement.
ACS applied materials interfaces