Comparison of tantalum and titanium (Alloy) as orthopedic materials: Physical and chemical indexes, antibacterial and osteogenic ability / 中国组织工程研究

BACKGROUND: Tantalum and titanium (alloy) are the most widely employed metallic biomaterials in orthopedics. Tantalum is especially focused because of its excellent corrosion resistance and osteointegration. However, whether tantalum is better than titanium (alloy) as orthopedic materials is still in dispute. OBJECTIVE: To review the comparative studies on the biological performances of tantalum and titanium (alloy) and analyze the possible causes of the similarities and differences of biocompatibility of tantalum and titanium (alloy) materials in vivo and in vitro. METHODS: A computer-based search of CNKI, Wanfang and PubMed database was performed for articles relating to the comparative studies on the biological performances of tantalum and titanium (alloy) published until January 2020. The search words were “tantalum” in title and “titanium” in title or abstract, i.e., (tantalum[Title])) AND (titanium[Title/Abstract]). RESULTS AND CONCLUSION: Among the comparative studies on the biological performances of tantalum and titanium (alloy), two viewpoints were primarily involved according to the results from clinical follow-up, animal tests, and cellular experiments. One is that tantalum is superior to titanium (alloy) with better osteogenesis and bone formation and stronger antibacterial activity, while the other one is that tantalum has similar osteogenesis and bone formation and antibacterial activity to titanium (alloy). The primary reason responsible for this divergence is that the fabrication method and the surface chemistries, topographical structures or pore structures are different between the employed tantalum and titanium (alloy).

Oriented collagen fiber membranes formed through counter-rotating extrusion and their application in tendon regeneration.

Well-aligned collagen fiber scaffolds are considered promising candidates for tendon tissue engineering in terms of their biomimetic chemical composition and topographic structure. Insoluble collagen fibers are more suitable for the preparation of scaffolds than soluble collagens due to their more approximate self-assembly and mechanical properties to native collagen ECMs. In this work, we employed counter-rotating extrusion technology for the first time to fabricate an aligned (CMa, orientation angle 0°-15°) and a randomly-oriented (CMr, orientation angle -60°-60°) collagen membrane from insoluble collagens. CMa had a tensile strength comparable with native rat Achilles tendon (18.45 ±â€¯0.91 MPa vs. 22.32 ±â€¯2.48 MPa). Thus, CMa represents a scaffold that is biomimetic of native tendon tissues in chemical composition, alignment, and mechanical properties. To verify the feasibility of CMs in tendon tissue engineering, we investigated the in vitro tenogenic differentiation of rBMSCs on CMs and the in vivo tendon regeneration using a rat Achilles tendon defect model. Detection of the tendon-related genes and proteins revealed that CMa can promote significantly higher tenogenic differentiation of rBMSCs than CMr, by inducing an elongated cell shape along the fibers. The in-situ tendon repair study further confirmed that CMa-BMSCs can produce a comparable healing quality to the autogenous tendon. Overall, our results verify the feasibility of the counter-rotating extrusion technology in fabricating biomimetic collagen scaffolds and provide a promising scaffold for tendon tissue regeneration.