Injectable Sealants Based on Silk Fibroin for Fast Hemostasis and Wound Repairing.

Uncontrollable blood loss poses fatality risks and most recently developed sealants still share common limitations on controversial components, degradability, mechanical strength or gelation time. Herein, series of injectable sealants based on silk fibroin (SF) is developed. Random coil/β-sheet conformation transition in SF is achieved by forming dendritic intermediates under induction of the structurally compatible and chemically complementary assembly peptide (Ac-KAEA-KAEA-KAEA-KAEA-NH , KA ). A ratio of 1:5 (KA-SF-15) shown an accelerating gelation process (≈12 s) and enhanced mechanical strength at physiological conditions. The interweaved nanofibers effectively impeded the bleeding within 30 s and no obvious adverse effects are observed. The supramolecular interactions and in vivo degradation benefit the inflammatory host cells infiltration and cytokines diffusion. Without any exogenous factors, the increased expression of VEGF and PDGF led to a positive feedback regulation on fibroblasts and vascular endothelial cell growth/proliferation and promoted the wound healing. These findings indicated the few assembly-peptide can accelerate fibroin gelation transition at a limited physiological condition, and the injectable amino acid-based sealants show obvious advantages on biocompatibility, degradability, rapid gelation and matched strength, with strong potential to act as next generation of biomedical materials.