Chemical and Environmental Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia.
ARC Centre of Excellence for Nanoscale BioPhotonics, School of Science, RMIT University, Melbourne, VIC 3000, Australia.
ACS Appl Bio Mater. 2021 Jul 19;4(7):5542-5555. doi: 10.1021/acsabm.1c00366. Epub 2021 Jun 21.
Magnesium (Mg) and its alloys are promising biodegradable metallic implant materials. However, their clinical applications are limited by their fast corrosion rate in the biological environment. In this work, with an outlook to improve the corrosion resistance of Mg and WE43 Mg alloy, a layer-by-layer interfacially engineered anticorrosive and bioactive coating consisting of a natural oxide lower layer, hydroxyapatite (HA) middle layer, and silk fibroin (SF) top layer was fabricated and investigated. Anodization was used to create natural oxide layer induced microroughness on substrates. The electrochemically deposited HA layer improved the surface microroughness and microhardness but significantly decreased Mg ion release, hydrogen gas evolution, and weight loss in simulated body fluid. The spin-coated SF layer further decreased hydrophilicity, degradation, and corrosion rate. The nonspecific and specific intermolecular interactions between fabricated layers along with their mechanical interlocking interface contributed to improved adhesion strength and integrity of the coating. The SF+HA-coated samples showed enhanced degradation and corrosion resistance due to a synergistic effect of the underlying HA layer, hindering the ingress of aggressive ions and the top hydrophobic SF layer, preventing the ingress of corrosive solution. The SF+HA-coated Mg and WE43 Mg alloy samples exhibited 50 and 26 times decreased corrosion rate, respectively, compared to uncoated samples. Moreover, cytotoxicity and cell culture studies using a mouse fibroblast cell showed that the SF+HA hybrid coating improved the cell viability, attachment, and proliferation, with cells exhibiting elongated morphology on coated samples as compared to a round shape on uncoated samples.
镁（Mg）及其合金是很有前途的可生物降解的金属植入材料。然而，由于其在生物环境中的腐蚀速度过快，其临床应用受到限制。在这项工作中，为了提高镁和 WE43 镁合金的耐腐蚀性，制备并研究了一种由天然氧化物底层、羟基磷灰石（HA）中层和丝素蛋白（SF）顶层组成的层层界面工程化的耐腐蚀和生物活性涂层。阳极氧化用于在基底上产生天然氧化物诱导的微粗糙度。电化学沉积的 HA 层提高了表面微粗糙度和显微硬度，但显著降低了镁离子释放、氢气析出和在模拟体液中的重量损失。旋涂的 SF 层进一步降低了亲水性、降解和腐蚀速率。制造层之间的非特异性和特异性分子间相互作用以及它们的机械联锁界面有助于提高涂层的附着力和完整性。SF+HA 涂层的样品由于底层 HA 层的协同作用，表现出增强的降解和耐腐蚀性，阻止了侵蚀性离子的进入和疏水的顶部 SF 层，防止了腐蚀性溶液的进入。与未涂层的样品相比，SF+HA 涂层的镁和 WE43 镁合金样品的腐蚀速率分别降低了 50 倍和 26 倍。此外，使用小鼠成纤维细胞进行的细胞毒性和细胞培养研究表明，SF+HA 杂化涂层提高了细胞活力、附着和增殖，与未涂层样品相比，细胞在涂层样品上呈现出伸长的形态，而在未涂层样品上呈现出圆形。
