Modulation of the Osteoimmune Environment in the Development of Biomaterials for Osteogenesis.

In spite of inherent regenerative ability of bone, large amounts of fracture patients still display delayed or compromised bone healing due to patients' age status, trauma severity or the developmental anomalies or infections, which requires therapeutic intervention. Bone regeneration involves different cells (immune cells, progenitors and mesenchymal stem cells, etc) and subsequent signaling molecules (chemokines, cytokines and growth factors, etc). The quantity and quality of immune cells influx into the site of injury and the subsequent cytokine production form a unique osteoimmune environment. Current strategies on repairing bone defects have largely focused on the development of suitable bone substitute materials, which may have potential osteoinductive, and/or osteoconductive properties. Various studies have been reported to develop the immuno-active or immunomodulatory biomaterials, which could fully explore the early osteoimmune environment in order to achieve better bone regeneration.