Zinc is emerging as a promising biodegradable metal for temporary implant applications. In this work, we investigate the influence of bovine serum albumin (BSA)—the most abundant blood protein in simulated body fluid (SBF) on degradation of pure Zn via electrochemical measurements and long-term immersion. Electrochemical experiments indicate a decrease of the corrosion rate of bare Zn with increasing BSA concentration in solution for short-term exposures. Samples were characterized with scanning electron microscope (SEM) (including energy dispersive spectroscopy [EDS], X-ray photoelectron spectroscopy [XPS], Fourier transform infrared spectroscopy [FTIR], and time-of-flight secondary ion mass spectrometry [TOF-SIMS]) after immersion up to 21 days. Presence of BSA in the electrolyte, decrease the amount of Ca-phosphate precipitation on Zn surface. However, a more compact surface layer formed in the presence of BSA in solution. Most noteworthy, in long-term exposures, BSA enhances localized corrosion of Zn—such detrimental localized attack was not observed in BSA-free solution. We suggest that a sealed space forming between the Zn substrate and a protein adsorption layer restricts mass transport, thus triggering localized corrosion of Zn.

中文翻译：

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牛血清白蛋白对纯锌生物降解行为的影响

锌正在成为一种有前途的可生物降解金属，可用于临时植入物应用。在这项工作中，我们通过电化学测量和长期浸泡研究了牛血清白蛋白 (BSA)（模拟体液 (SBF) 中最丰富的血液蛋白）对纯锌降解的影响。电化学实验表明，对于短期暴露，随着溶液中 BSA 浓度的增加，裸 Zn 的腐蚀速率会降低。使用扫描电子显微镜 (SEM) 对样品进行表征（包括能量色散光谱 [EDS]、X 射线光电子能谱 [XPS]、傅里叶变换红外光谱 [FTIR] 和飞行时间二次离子质谱 [TOF-SIMS] ]) 浸泡 21 天后。电解液中 BSA 的存在，减少了 Zn 表面的磷酸钙沉淀量。然而，在溶液中存在 BSA 时会形成更致密的表面层。最值得注意的是，在长期暴露中，BSA 会增强 Zn 的局部腐蚀——在不含 BSA 的溶液中没有观察到这种有害的局部腐蚀。我们建议在锌基板和蛋白质吸附层之间形成的密封空间限制了质量传递，从而引发了锌的局部腐蚀。