Bone regeneration of rat calvarial defect using biomimetic keratin-based membranes

Effective guided bone regeneration (GBR) relies on barrier membranes that prevent soft tissue infiltration and create a protected environment conducive to osteogenesis. Current membranes, primarily derived from collagen, often exhibit premature resorption, insufficient stability, limited osteoinductivity, and potential immunogenicity. These shortcomings are particularly problematic in large, unstable, or load-bearing defects, where collapse or inflammation can compromise outcomes. Here, we report the development of keratin-based membranes stabilized through intrinsic protein interactions and controlled crosslinking, as a bioinstructive and sustainable alternative for GBR. Primary human bone marrow stromal cells cultured on keratin membranes exhibited high viability and sequential osteogenic differentiation, with significant upregulation of both early and late osteogenic markers. In a rat critical-size calvarial defect model, keratin membranes supported soft tissue integration, defect bridging, and bone regeneration with organized tissue architecture. Micro-CT and histological analyses revealed that although collagen membranes produced higher overall bone volume, keratin scaffolds were associated with more spatially organized bone tissue and collagen architecture. These findings suggest that keratin membranes act not as passive barriers but as bioactive substrates that support coordinated osteogenesis and tissue maturation. This study highlights keratin as a scalable and clinically viable GBR platform, combining structural stability, bioactivity, and sustainability.