Europium-Doped 3D Dimensional Porous Calcium Phosphate Scaffolds as a Strategy for Facilitating the Comprehensive Regeneration of Bone Tissue: In Vitro and In Vivo.

In response to the challenges faced by clinicians treating bone defects caused by various factors, various bone repair materials have been investigated, but the efficiency of bone healing still needs to be improved due to the acting of scaffolds only in a single stage of bone tissue regeneration. We investigated the potential of a novel 3D scaffold to support different stages of bone tissue regeneration, including initial inflammation, proliferation, and remodeling. Eu (0, 0.5, 2, 3.5, 5, and 6.5%) was added to calcium polyphosphate to obtain 3D porous network-doped Eu calcium polyphosphate (EuCPP) scaffolds with ideal mechanical strength and pore size. Both in vitro and in vivo experiments proved that Eu released from 5% EuCPP scaffolds could significantly promote the migration and proliferation of bone marrow stromal cells which effectively promote angiogenesis; 5% EuCPP could significantly upregulate the ratio of OPG/RANKL in MC3T3-E1 and promote the secretion of osteogenic-related growth factors (ALP and OPN) from MC3T3-E1, indicating the potential of the scaffold to inhibit bone resorption and promote bone formation. In conclusion, 5% EuCPP possesses the biological properties of pro-angiogenesis, anti-inflammation, pro-osteogenesis, and inhibiting bone resorption, which may provide a sustained positive effect throughout the process of bone tissue repair.