A bioinspired mineral-organic composite hydrogel as a self-healable and mechanically robust bone graft for promoting bone regeneration

Abstract

Despite advances in the development of osteo-regenerative biomaterials, current products are vulnerable to stress-induced formation of cracks, resulting in the loss of functionality and a limited lifespan. In the present study, a strategy based on host-guest assembly was developed to fabricate a silk fibroin-based inorganic-organic hybrid hydrogel (termed SF@HG@HA) in which silk fibroin was used as a polymer template to tether host (β-cyclodextrin) and guest (cholesterol) monomers, respectively. Due to dynamic host-guest interactions, the prepared hydrogel could repair itself spontaneously when damaged, without the assistance of any external stimuli, mimicking the self-healing characteristics of native bone tissue. Furthermore, the efficient energy dissipation mechanism provided by the host-guest crosslinking strategy endowed the hydrogel with robust mechanical properties to bear substantial mechanical loading. SF@HG@HA was shown to support cell proliferation and osteogenic differentiation in vitro and accelerate bone regeneration in critical-size rat femoral defects in vivo. Together, the silk fibroin-based self-healing hydrogel with robust mechanical properties shows potential applications in the reconstruction of bone defects, which may provide new directions for the design of functional biomaterials for tissue regeneration.