Nitinol is commonly used in medical implants due to its unique thermomechanical properties of shape memory and superelasticity. Free nickel has the potential to induce biological responses that may be a concern for permanent implants manufactured from nickel‐containing alloys. Although there are extensive reports on the effects of surface treatments on corrosion behavior in cardiovascular Nitinol implants, there is a lack of data on corrosion resistance and impact on biocompatibility for ocular implants. Therefore, the objective of this study was to determine localized corrosion and nickel elution resistance of an electropolished Nitinol‐based ocular device (Hydrus Microstent, Ivantis, Inc.) intended for patients with primary open angle glaucoma. Pitting corrosion susceptibility was characterized by potentiodynamic polarization testing per ASTM F2129. In addition, nickel ion release was quantified with immersion testing to 63 days. The results indicated high localized corrosion resistance as all samples reached polarization potentials of 800 mV without pitting initiation. Maximum nickel elution rates per device were less than approximately 1.1 ng/device/day after the first day of immersion and reduced to less than 0.1 ng/device/day after 7 days. For a patient with bilateral microstents, these nickel concentrations are ×10,000 lower than previously published tolerable intake levels for systemic toxicity. Overall, these corrosion results are in good agreement with literature values of well processed and biocompatible Nitinol devices indicating adverse systemic biological responses are not expected in vivo.

中文翻译：

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镍钛诺眼部微型支架的耐腐蚀性：对生物相容性的影响。

镍钛诺因其独特的形状记忆和超弹性热机械特性而常用于医疗植入物。游离镍有可能引起生物反应，这可能是由含镍合金制成的永久性植入物的一个问题。尽管有大量关于表面处理对心血管镍钛诺植入物腐蚀行为影响的报道，但缺乏关于眼部植入物的耐腐蚀性和生物相容性影响的数据。因此，本研究的目的是确定用于原发性开角型青光眼患者的电抛光镍钛诺眼部装置（Hydrus Microstent，Ivantis，Inc.）的局部腐蚀和镍洗脱阻力。根据 ASTM F2129，通过动电位极化测试表征点腐蚀敏感性。此外，镍离子释放量通过浸入测试量化为 63 天。结果表明高局部耐腐蚀性，因为所有样品都达到了 800 mV 的极化电位，而没有发生点蚀。在浸入的第一天后，每个设备的最大镍洗脱率低于大约 1.1 ng/设备/天，并在 7 天后降至低于 0.1 ng/设备/天。对于双侧微型支架患者，这些镍浓度比之前公布的全身毒性可耐受摄入量低 10,000 倍。总体，