Fabrication of 3D printed Ca3Mg3(PO4)4-based bioceramic scaffolds with tailorable high mechanical strength and osteostimulation effect

Calcium, magnesium and phosphate are predominant constituents in the human bone. In this study, magnesium-calcium phosphate composite bioceramic scaffolds were fabricated utilizing Mg3(PO4)2 and β-Ca3(PO4)2 as starting materials, and their pore structure was constructed by 3D printing. The porosity and compressive strength of the composite bioceramic scaffolds could be adjusted by altering the sintering temperature and the formula of starting materials. The composite bioceramic scaffolds prepared from 60 wt% Mg3(PO4)2 and 40 wt% β-Ca3(PO4)2 were dominated by the Ca3Mg3(PO4)4 phase, and this Ca3Mg3(PO4)4-based bioceramic scaffolds possessed the highest compressive strength (12.7 - 92.4 MPa). Moreover, the Ca3Mg3(PO4)4-based bioceramic scaffolds stimulated cellular growth and osteoblastic differentiation of bone marrow stromal cells. The Ca3Mg3(PO4)4-based bioceramic scaffolds as bone regenerative biomaterials are flexible to the requirement of bone defects at various sites.

Extracorporeal Shock Wave Combined with Teriparatide-Loaded Hydrogel Injection Promotes Segmental Bone Defects Healing in Osteoporosis

BACKGROUND

Osteoporosis is a systemic bone disease characterized by decreased bone density and deterioration of bone microstructure, leading to an increased probability of fragility fractures. Once segmental bone defect occurs, it is easy to cause delayed union and nonunion.

METHODS

The aim of this study is to investigate the efficacy of extracorporeal shock wave (ESW) and teriparatide-loaded hydrogel (T-Gel) combined strategy on the cell activity and differentiation of osteoporosis derived bone marrow mesenchymal stem cells (OP-BMSCs) in vitro and bone regeneration in osteoporotic segmental bone defects in vivo.

RESULTS

In vitro, the strategy of combining ESW and T-Gel significantly enhanced OP-BMSCs proliferation, survival, migration, and osteogenic differentiation by up-regulating the alkaline phosphatase activity, mineralization, and expression of runt-related transcription factor-2, type I collagen, osteocalcin, and osteopontin. In the segmental bone defect models of osteoporotic rabbits, Micro-CT evaluation and histological observation demonstrated this ESW-combined with T-Gel injection significantly induced bone healing by enhancing the osteogenic activity of the local microenvironment in osteoporotic defects.

CONCLUSION

In conclusion, ESW-combined with T-Gel injection could regulate the poor osteogenic microenvironment in osteoporotic defects and show potential for enhancing fragility fractures healing.

Locally Controlled Diffusive Release of Bone Morphogenetic Protein-2 Using Micropatterned Gelatin Methacrylate Hydrogel Carriers

In this work, a novel and simple bone morphogenetic protein (BMP)-2 carrier is developed, which enables localized and controlled release of BMP-2 and facilitates bone regeneration. BMP-2 is localized in the gelatin methacrylate (GelMA) micropatterns on hydrophilic semi-permeable membrane (SNM), and its controlled release is regulated by the concentration of GelMA hydrogel and BMP-2. The controlled release of BMP-2 is verified using computational analysis and quantified using fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) diffusion model. The osteogenic differentiation of osteosarcoma MG-63 cells is manipulated by localized and controlled BMP-2 release. The calcium deposits are significantly higher and the actin skeletal networks are denser in MG-63 cells cultured in the BMP-2-immobilized GelMA micropattern than in the absence of BMP-2. The proposed BMP-2 carrier is expected to not only act as a barrier membrane that can prevent invasion of connective tissue during bone regeneration, but also as a carrier capable of localizing and controlling the release of BMP-2 due to GelMA micropatterning on SNM. This approach can be extensively applied to tissue engineering, including the localization and encapsulation of cells or drugs.