Sequence-Engineered Recombinant Human Collagen as a Biomacromolecular Platform for Guided Bone Regeneration Membranes

Effective repair of bone defects remains a major clinical challenge. Guided bone regeneration (GBR) membranes promote bone regeneration by preventing soft-tissue invasion; however, synthetic membranes often exhibit limited bioactivity, whereas animal-derived collagen membranes face concerns related to source safety, immunogenicity, and batch variability. Here, we developed a sequence-engineered recombinant human collagen (rhCol)-based biomaterial platform and fabricated a degradable bilayer membrane (rhColM) through dehydrothermal treatment free of exogenous chemical crosslinkers. rhColM exhibited a tensile strength of 5.44 MPa, a porosity of 76.26%, and an asymmetric architecture consisting of a dense barrier layer and a porous bone-facing layer. In rat subcutaneous implantation, rhColM showed favorable biocompatibility without obvious inflammatory cell infiltration or connective tissue penetration at 1 and 3 weeks. In a rabbit lateral femoral condyle defect model, rhColM increased bone volume fraction to 42.54%, 90.70% and 99.41% at 4, 8 and 12 weeks, respectively, compared with 36.19%, 76.36% and 90.15% in controls. Histological analysis revealed progressive bone formation along the rhColM interface and substantial defect repair with lamellar bone-like tissue by 8 weeks, while rhColM was no longer visibly detected. These findings highlight sequence-engineered rhCol as a promising and source-defined biomacromolecular platform for developing recombinant collagen-based GBR membranes.