ABSTRACT
[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
ABSTRACT
[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
ABSTRACT
[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.