Barrier Membrane\nwith Janus Function and Structure\nfor Guided Bone Regeneration

Guided bone regeneration (GBR) technology has been demonstrated\nto be an effective method for reconstructing bone defects. A membrane\nis used to cover the bone defect to stop soft tissue from growing\ninto it. The biosurface design of the barrier membrane is key to the\ntechnology. In this work, an asymmetric functional gradient Janus\nmembrane was designed to address the bidirectional environment of\nthe bone and soft tissue during bone reconstruction. The Janus membrane\nwas simply and efficiently prepared by the multilayer self-assembly\ntechnique, and it was divided into the polycaprolactone isolation\nlayer (PCL layer, GBR-A) and the nanohydroxyapatite/polycaprolactone/polyethylene\nglycol osteogenic layer (HAn/PCL/PEG layer, GBR-B). The morphology,\ncomposition, roughness, hydrophilicity, biocompatibility, cell attachment,\nand osteogenic mineralization ability of the double surfaces of the\nJanus membrane were systematically evaluated. The GBR-A layer was\nsmooth, dense, and hydrophobic, which could inhibit cell adhesion\nand resist soft tissue invasion. The GBR-B layer was rough, porous,\nhydrophilic, and bioactive, promoting cell adhesion, proliferation,\nmatrix mineralization, and expression of alkaline phosphatase and\nRUNX2. In vitro and in vivo results showed that the membrane could\nbind tightly to bone, maintain long-term space stability, and significantly\npromote new bone formation. Moreover, the membrane could fix the bone\nfilling material in the defect for a better healing effect. This work\npresents a straightforward and viable methodology for the fabrication\nof GBR membranes with Janus-based bioactive surfaces. This work may\nprovide insights for the design of biomaterial surfaces and treatment\nof bone defects.