镍钛合金表面钛、钛铌涂层防止Ni^(2+)析出实验研究

Study on separation of Ni^(2+) of Nitinol modified on its surfaces by the coating of titanium or titanium-niobium alloy

目的:探讨镍钛记忆合金(以下简称NiTi)及表面钛、钛铌合金涂层后Ni2+在体内、外试验中的析出情况。方法:体外采用生理盐水浸泡试验,于试验后1~7d采样,石墨炉原子吸收仪(GFAAS)法测定各组生理盐水中Ni2+浓度。体内试验选取成年犬18只,分别于骶棘肌和股骨内植入立方体和圆柱型植入体各10枚,12个月后处死取材,采用GFAAS分别检测心、肝、脾等组织的Ni2+含量。结果:表面未经钛、钛铌涂层修饰的NiTi Ni2+有明显析出,以前4d为主,其吸出率(10-7μg·cm-2·s-1)分别为18.2、3.45、1.75和0.45,第5d后Ni2+无明显析出。经钛、钛铌修饰后Ni2+无明显析出。该实验的样品回收率为94.6%~108.6%。体内非修饰的NiTi组植入体周围的骨组织和肌肉组织的Ni2+含量与同组同种组织、异组同种组织的Ni2+含量有显著差异(P<0.05)。结论:体内、外试验的结果均表明,钛、钛铌涂层修饰起到了防止或减少Ni2+吸出作用。

Objective： To investigate whether Ni^2＋ of the Nitinol and Nitinol modified on its surfaces by the coating of metallic titanium and titanium-niobium alloy was separated or not in vivo and in vitro. Methods：In vitro, we collected the specimens from 1 to 7 days after the experiments and determined the concentration of Ni^2＋ by physiologic saline immersing test and by using graphite furnace atomic absorption spectrometry （GFAAS）. In vivo, 18 adult dogs were selected randomly, the cubic implants were imbedded in the muscle by the sides of saerespinalis and the cylinder in the femurs, 10 pieces of each kinds of implants were imbedded respectively in each dog, drawing the materials by killing them after 12 months from the experiments and assaying the concentration of Ni^2＋ of the hearts, livers, spleens, and so on by GFAAS. Results： In vitro, obvious separation of Ni^2＋ was detected in the group of Nitinol that was not modified, the separating procedure was mairdy within the first 4 clays, the separation rate （10^-7μg·cm^-2·s^-1） from the first to the forth days was 18.2, 3.45, 1.75 and 0.45 respectively, the Ni^2＋ was no more separated from the fifth day. Whereas, Ni^2＋ was not separated in group of Nitinol that was modified by the coating of metallic Ti and TiNb alloy. The recovery rate of the experiment was 94.6% -108.6%. In vivo, the content of Ni^2＋ around implants not modified implants was obvious differenee（P 〈0.05 ）compared to modified groups, either in bone or in muscle tissues, either in the same group and the same kind of tissue or in the different groups and the same kind of tissue. Condusion： Either in vitro or in vivo, the coating by Ti or by TiNb alloy on the surfaces of Nitinol stopped or decreased Nitinol from separating Ni^2＋.