Green Tea Polyphenol Induced Mg2 -rich Multilayer Conversion Coating: Toward Enhanced Corrosion Resistance and Promoted in Situ Endothelialization of AZ31 for Potential Cardiovascular Applications
Green Tea Polyphenol Induced Mg2 -rich Multilayer Conversion Coating: Toward Enhanced Corrosion Resistance and Promoted in Situ Endothelialization of AZ31 for Potential Cardiovascular Applications
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绿茶多酚诱导富含 Mg2 的多层转化涂层：增强 AZ31 的耐腐蚀性并促进原位内皮化，在心血管领域具有潜在应用
DOI：
10.1021/acsami.9b17221
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发表时间：
2019
影响因子：
9.5
通讯作者：
Wang Yunbing
中科院分区：
文献类型：
--
作者：
Zhang Bo;Yao Ruijuan;Li Linhua;Wang Yanan;Luo Rifang;Yang Li;Wang Yunbing
镁及其合金作为一种有前途的可生物降解金属材料，近十年来受到人们的广泛关注。然而，由于其高腐蚀率和植入后生物相容性不足，仍然存在挑战。本文采用逐层沉积法在镁合金（AZ 31）表面制备了一种简单、通用的绿色茶多酚-金属诱导多层转化膜（Mg ~（2+）掺杂表没食子儿茶素没食子酸酯（EGCG）膜）。表面形貌分析结果表明，Mg 2+的引入使EGCG/Mg复合膜中苯酚-Mg复合物含量增加，膜层形貌更加均匀致密，裂纹减少。通过电化学腐蚀试验、pH值变化和析氢监测等方法研究了AZ 31的体外降解速率和耐腐蚀性能。结果表明，与裸AZ 31相比，经EGCG/Mg涂层保护后，AZ 31的腐蚀速率明显降低。体外和离体血栓形成试验表明，与AZ 31裸涂层相比，EGCG/Mg涂层在降低血小板和红细胞的粘附和活化、活化部分凝血活酶时间（APTT）和抗血栓形成等方面均有显著改善。由于其降解速率较低，结合EGCG的生物学功能，可增强AZ 31镁合金表面内皮细胞（EC）的粘附和增殖，抑制平滑肌细胞（SMCs）的粘附和增殖，抑制细胞因子的释放。此外，在体内皮下包埋实验表明，由于提高了对周围微环境的耐腐蚀性，EGCG/Mg涂层表现出更温和的组织反应。此外，对于在体腹主动脉测定，与裸AZ 31丝相比，EGCG/Mg涂覆的AZ 31丝呈现出更好的耐腐蚀性和增强的再内皮化。这些结果表明，使用绿色茶多酚诱导的富含Mg 2+的多层转化涂层用于增强可生物降解的心血管植入物的腐蚀保护和期望的生物相容性的潜力。
As a promising biodegradable metallic material, magnesium (Mg) and its alloys have attracted special attention in the recent decade. However, challenges still remain due to its high corrosion rate and insufficient biocompatibility after implantation. In this work, we prepare a simple and versatile green tea phenol–metal induced multilayer conversion coating (Mg2+incorporated epigallocatechin gallate (EGCG) coating) on magnesium alloys’ (AZ31) substrate by layer-by-layer (LBL) method. The surface morphology results revealed that, with the incorporation of Mg2+, the as-formed EGCG/Mg coating was rich in phenol–Mg complex and presented more homogeneous and dense morphology, with far less cracks than the pure EGCG coating. The in vitro degradation rate and corrosion resistance were studied by electrochemical corrosion tests and monitoring of the changed pH value and hydrogen evolution, respectively, which revealed that the corrosion rate was effectively decreased compared to that of bare AZ31 after it was protected by EGCG/Mg coating. In vitro and ex vivo thrombogenicity test demonstrated the EGCG/Mg coatings presented an impressive improvement in decreasing the adhesion and activation of platelets and erythrocytes, in activated partial thromboplastin time (APTT), and in antithrombogenicity compared to those of bare AZ31. Owing to the mild degradation rate, in combination with the biological function of EGCG, enhanced endothelial cells’ (ECs’) adhesion and proliferation, suppressed smooth muscle cells’ (SMCs’) adhesion/proliferation, and inhibited cytokine release were observed on EGCG/Mg coated AZ31 alloy. Besides, the in vivo subcutaneous embedding experiment suggested that the EGCG/Mg coating performed more mild tissue response due to the improved corrosion resistance to the surrounding microenvironment. Moreover, for in vivo abdominal aorta assay, the EGCG/Mg coated AZ31 wire presented better corrosion resistance and enhanced re-endothelialization compared to bare AZ31 wire. These results suggested the potential of using green tea polyphenol induced Mg2+-rich multilayer conversion coating for enhanced corrosion protection and desired biocompatibility of biodegradable cardiovascular implants.