Merritt K, Brown S A
Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106.
J Biomed Mater Res. 1988 Feb;22(2):111-20. doi: 10.1002/jbm.820220204.
The objectives of this study were to determine the effect of proteins and protein charge on the corrosion of stainless steel. As Zwitter ions, proteins have a positive charge in solutions acidic to their isoelectric point (pI) and a negative charge in solutions basic to the pI. Fretting corrosion rates of stainless-steel plates and screws as determined by weight loss and metal ion release were studied in saline and protein solutions with the pH adjusted to 3, 5, and 8. Alterations in pH did not affect the corrosion rate in saline solutions. However, alterations of the pH in albumin solutions did affect the corrosion rate. In protein solutions acidic to the isoelectric point the presence of the positively charged albumin did not alter the corrosion rates as compared to that in saline. However, the presence of negatively charged proteins in solutions basic to their isoelectric points decreased the amount of corrosion. Thus, the effect of proteins on fretting corrosion is dependent on the charge on the protein. When the release of nickel was compared to the release of chromium, it was shown that the release was in proportion to the composition of the alloy when fretting corrosion took place in saline. The nickel/chromium ratio in the albumin and gamma globulin solutions was increased relative to that predicted indicating preferential release of nickel in protein solutions.
本研究的目的是确定蛋白质及其电荷对不锈钢腐蚀的影响。作为两性离子，蛋白质在酸性至其等电点（pI）的溶液中带正电荷，而在碱性至pI的溶液中带负电荷。通过失重和金属离子释放测定不锈钢板和螺钉在pH值分别调节为3、5和8的生理盐水和蛋白质溶液中的微动腐蚀速率。pH值的变化对生理盐水溶液中的腐蚀速率没有影响。然而，白蛋白溶液中pH值的变化确实会影响腐蚀速率。在酸性至等电点的蛋白质溶液中，带正电荷的白蛋白的存在与生理盐水中相比并没有改变腐蚀速率。然而，在碱性至其等电点的溶液中带负电荷的蛋白质的存在减少了腐蚀量。因此，蛋白质对微动腐蚀的影响取决于蛋白质上的电荷。当将镍的释放量与铬的释放量进行比较时，结果表明，在生理盐水中发生微动腐蚀时，释放量与合金成分成比例。白蛋白和γ球蛋白溶液中的镍/铬比值相对于预测值增加，表明在蛋白质溶液中镍优先释放。
