The present invention is about direct protein delivery system for bone morphogenetic proteins (BMPs) to enhance bone regeneration without the need of additional delivery carrier which requires open surgery for their implantation. The cell-permeable BMP (CP-BMP) recombinant proteins are fused with advanced macromolecule transduction domain (aMTD) to give them ability for cell penetration and with solubilization domain (SD) to increase their solubility and manufacturing yield. Because existing BMP recombinant proteins have short half-life, they have been delivered with polymeric or inorganic vehicles for their sustained release. However, CP-BMPs fused to combination of aMTD and SD can easily and rapidly penetrate into the cytosol after treating on cells that likes hiding in a shelter from wash off in body fluid, and avoid rapid degradation. For the development of CP-BMP, BMP2 and BMP7 have been selected among various types of BMP family due to their potent osteo-inductivity. Both of proteins are produced in mature form (MP) as an active domain and pro-peptide form (latency associated peptide (LAP)+MP) for prolonged stability of proteins. In the present art, three strategic steps are used to prove the validity of using CP-BMPs on bone regeneration and new bone formation. First, randomly selected aMTDs and various types of SDs have been fused to BMP proteins for determine the best structural composition for highest solubility/yield and cell-/tissue-permeability. Next, aMTDs are fused to BMP2 and BMP7 proteins with optimized structure to determine the best construct for maximized cell- and tissue-permeability. Finally, biological activity of BMP2, BMP7 and combination of BMP2 and BMP7 recombinant proteins have been evaluated to enhance in vitro osteogenic differentiation and in vivo bone regeneration. The CP-BMPs can be applied to repair skeletal injuries which are by bone fracture, osteogenesis imperfecta, and bone extraction.
