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[Objective]To develop new beta titanium alloys made of titanium, niobium and zirconium (Ti-Nb-Zr) which have higher strength, lower moduli of elasticity. Its biocompatibility in vivo is evaluated in this paper. [Method](1) 24 SD rats were used in the modified air pouch model experiments. Air was injected subcutaneously on the back of rats to form the pouches and the Ti-Nb-Zr particles were introduced into them. The liquid in the pouches was harvested 48 hours later for IL-6 and TNF-?ELISA procedure and the capsules for histology examination. All the results were compared with Ti-6Al-4V. (2) Ti-Nb-Zr bone plates were fixed onto tibias of rabbits. The capsules around the plates and the bone under them were observed at 4, 8, 12, 24 and 36 weeks respectively. Ti-Nb-Zr-bone interfaces were emphasized in this procedure. This time the control material was stainless steel. [Result](1)Ti-Nb-Zr and Ti-6Al-4V particles made the air pouches secret more TNF-? than that of the control (P
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[Objective]To evaluate the biocompatibility of a new bate titanium alloys made of titanium, niobium and zirconium (Ti-Nb-Zr) which have higher strength and lower elastic modulus by in vitro study.[Method](1)the cell toxicity of Ti-Nb-Zr was evaluated using L-929 cell line's relative growth rate (RGR) which was transformed into 6 toxicity ranks in according with the national standard;(2)the J774A.1macrophages cultured with Ti-Nb-Zr particles whose diameter was about 1 ?m for 24-48 hours were observed using inverted phase contrast microscopy and transmission electron microscopy. Expression of IL-6 and TNF-? mRNA in these cells were measured using RT-PCR technique. The TNF-? in the supernatant was also measured using ELISA method. All the results were compared with the traditional orthopedic implants metal materials such as Ti-6Al-4V and Co-Gr-Mo.[Result]The cell toxicity of Ti-Nb-Zr was ranked zero degree. The particles could be seen in the macrophages under the light microscopy. Ti-Nb-Zr particles made the J774.A1 macrophages less configurative changes than Ti-6Al-4V and Co-Gr-Mo did.Expressions of IL-6 and TNF-? mRNA in J774.A1 cell were increased after stimulation for 48 hours by all kinds of metallic materials. The TNF-? in the supernatants of Ti-Nb-Zr group were less than that of the Ti-6Al-4V and Co-Gr-Mo groups (P
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[Objective] To develop new bate titanium alloys made of titanium,niobium and zirconium(Ti-Nb-Zr)which have higher strength,lower moduli of elasticity and better biocompatibility for orthopedic implants.[Methods]Alloy elements including titanium,niobium and zirconium were melted together and forged into forging Ti-Nb-Zr.Four kinds of alloys were developed because of the different proportion of alloy elements.All alloys were studied using X-ray diffraction analysis,biomechanical measurements,and scanning and transmission electron microscopy.[Results]X-ray diffraction analyses showed that all the candidates were beta alloys.The as-cast alloys had the strength values in 584~718 Mpa,elastic modulus values in 59~68 Gpa.The peak-aged alloys had the strength values in 706~874 Mpa,elastic modulus values in 59~66 Gpa,elongation rates in 5.4%~20%.The forging procedure could increase the strength significantly but almost have no influence in elastic modulus of Ti-Nb-Zr.[Conclusion]The Ti-Nb-Zr beta titanium alloys developed in our lab have lower modulus and high strength both.It is a promising material for orthopedic implants.
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Hydroxyapatite has been considered as the most promising materials for hard tissue replacements, due to its similar chemical composition and crystallographic structure to that of bone mineral. But the brittleness is one of the most serious obstacles for its wider applications as load-bearing implants. Therefore, various HA composites get much attention. In the present paper, HA composites were introduced according to the kind of reinforcement. Although bioactive ceramics, bioactive glass or glass-ceramic, bio-inactive ceramics, polymers and metals all have been used to fabricate HA composites, no one can well satisfy the requirements for hard tissue replacement. The vital problem of the existing HA composites is that the biological properties cannot match with the mechanical properties well.