Titanium-based composite scaffolds reinforced with hydroxyapatite-zirconia: Production, mechanical and in-vitro characterization

Tribological behavior and in vitro biocompatibility of powder metallurgical Ti-15Mo/HA composite for bone repair

Ti-15Mo/HA composite was prepared by powder metallurgy, and the influence of Hydroxyapatite (HA) on the microstructure, tribological behavior and in vitro biocompatibility was studied by comparison with TC4. The results show that the Ti-15Mo/HA composite consists of increased α-Ti, decreased β-Ti and a variety of ceramic phases (CaTiO3, Ca3(PO4)2, CaO, etc.) with the increase of HA content. The friction coefficient and wear rate of Ti-15Mo/HA composite is apparently lower than those of TC4 due to solid solution strengthening of Mo in Ti and dispersion strengthening of ceramic phases. Ti-15Mo/5HA displays more excellent wear resistance than the other composite. TC4 alloy is dominated by adhesive wear, however, Ti-15Mo alloy is a combination of adhesive wear and abrasive wear. Ti-15Mo/HA composite is mainly subjected to abrasive wear, together with adhesive wear. The viability and the number of mouse osteoblasts in Ti-15Mo/5HA extract are higher than that of Ti-15Mo. The morphology of the osteoblasts is clear and full, and the growth and proliferation are satisfactory with the increased cell pseudopodia with the culture time. The Ti-15Mo/HA composite displays good wear resistance and biocompatibility, and accordingly has a potential application in bone repair materials.

Metal Ion-Doped Hydroxyapatite-Based Materials for Bone Defect Restoration

Hydroxyapatite (HA)-based materials are widely used in the bone defect restoration field due to their stable physical properties, good biocompatibility, and bone induction potential. To further improve their performance with extra functions such as antibacterial activity, various kinds of metal ion-doped HA-based materials have been proposed and synthesized. This paper offered a comprehensive review of metal ion-doped HA-based materials for bone defect restoration based on the introduction of the physicochemical characteristics of HA followed by the synthesis methods, properties, and applications of different kinds of metal ion (Ag+, Zn2+, Mg2+, Sr2+, Sm3+, and Ce3+)-doped HA-based materials. In addition, the underlying challenges for bone defect restoration using these materials and potential solutions were discussed.

The practical process of manufacturing poly(methyl methacrylate)-based scaffolds having high porosity and high strength

Poly(methyl methacrylate) (PMMA)-based scaffolds have been produced using the granule casting method with grain sizes M80-100 and M100-140. The novelty of this study was the application of the cold-cutting method (CCm) to reduce the PMMA granule size. PMMA granule shape, granule size (mesh), and sintering temperature were the primary variables in manufacturing PMMA scaffolds. CCm was applied to reduce the granule size of commercial PMMA, which was originally solid cylindrical, by lowering the temperature to 3.5 °C, 0 °C, and-8.3 °C. PMMA granules that had been reduced were sieved with mesh sizes M80-100 and M100-140. Green bodies were made by the granule casting method using an aluminum mold measuring 8 × 8 × 8 mm³. The sintering process was carried out at temperatures varying from 115 °C to 140 °C, a heating rate of 5 °C/min, and a holding time of 2 h, the cooling process was carried out in a furnace. The characterization of the PMMA-based scaffolds' properties was carried out by observing the microstructure with SEM, analyzing the distribution of pore sizes with ImageJ software, and testing the porosity, the phase, with XRD, and the compressive strength. The best results from the overall analysis were the M80-100 PMMA scaffold treated at a sintering temperature of 130 °C with compressive strength, porosity, and pore size distribution values of 8.2 MPa, 62.0%, and 121-399 μm, respectively, and the M100-140 one treated at a sintering temperature of 135 °C with compressive strength, porosity, and pore size distribution values of 12.1 MPa, 61.2%, and 140-366 μm, respectively. There were interconnected pores in the PMMA scaffolds, as evidenced by the SEM images. There was no PMMA phase change between before and after the sintering process.