镁合金腐蚀研究进展（22）—镁合金表面聚硅氧烷纳米银涂层耐蚀与抗菌性

    镁合金因具有良好的生物相容性和可降解性，可作为短时生物植入体植入人体，避免二次手术将其移除所带来的痛苦和医疗费用。然而，限制镁合金应用的主要因素是其耐腐蚀性差。

    目前比较有效的解决方法之一是利用聚硅氧烷在镁合金表面改性。这是因为硅氧烷可以在镁合金表面形成Si-O-Si键，形成物理屏障保护层，提高镁合金的耐蚀性。我们已在镁合金表面构建聚甲基三甲氧基硅烷/微弧氧化复合涂层以提高其耐蚀性（Corrosion Science,2017, http://dx.doi.org/10.1016/j.corsci.2017.01.025）。

   然而，医用可降解镁合金聚硅氧烷涂层可能有发生细菌感染的风险，增加早期植入体的移植失败率。因此，有必要在该涂层中掺入有效的抗菌剂。纳米银（silver nanoparticles，AgNPs）作为广谱抗菌剂，具有低毒性，可以用作镁合金抗菌剂。层层组装（layer-by-layer，LbL）技术是目前制备纳米银/聚电解质含银涂层的有效的方法。

    研究发现，镁合金表面聚硅氧烷修饰纳米银层层组装复合涂层具有很好的耐腐蚀性和抗菌性。特别是，该涂层具有自修复性能，并且能够延长银离子的释放时间。该项工作“Corrosion resistance and antibacterial properties of polysiloxane modified layer-by-layer assembled self-healing coating on magnesium alloy”在线发表在 Journal of Colloid & Interface Science (IF5.091)。

Abstract

Magnesium (Mg) alloys have shown great potential in biomedical materials due to their biocompatibility and biodegradability. However, rapid corrosion rate, which is an inevitable obstacle, hinders their clinical applications. Besides, it is necessary to endow Mg alloys with antibacterial properties, which are crucial for temporary implants. In this study, silver nanoparticles (AgNPs) and polymethyltrimethoxysilane (PMTMS) were introduced into AZ31 Mg alloys via layer-by-layer (LbL) assembly and siloxane self-condensation reaction. The characteristics of the composite films were investigated by SEM, UV-vis, FT-IR, and XRD measurements. Corrosion resistance of the samples was measured by electrochemical and hydrogen evolution tests. Antibacterial activities of the films against Staphylococcus aureus were evaluated by plate-counting method. The results demonstrated that the composite film with smooth and uniform morphologies could enhance the corrosion resistance of Mg alloys owing to the physical barrier and the self-healing functionality of polysiloxane. Moreover, the composite coating possessed antibacterial properties and could prolong the release of assembled silver ions.

Keywords

Layer-by-layer; Corrosion resistance; Antibacterial property; Self-healing; Magnesium alloy; Silver nanoparticles.

Graphical Abstract

The PMTMS/(AgNPs/PEI)₅ film developed on the surface of Mg alloy could enhance the corrosion resistance and antibacterial properties, while it possessed self-healing performance and prolonged the release of Ag⁺ ions.

链接：曾荣昌发表论文目录（Rong-Chang Zeng's Publications）(2000-)