Bionic Tea Stain–Like, All‐Nanoparticle Coating for Biocompatible Corrosion Protection. Issue 20 (28th August 2019)

• Record Type: Journal Article
• Authors: Zhang, Bo; Yao, Ruijuan; Li, Linhua; Li, Mingyu; Yang, Li; Liang, Zhen; Yu, Hongchi; Zhang, Hao; Luo, Rifang; Wang, Yunbing
• Is Part Of: Advanced materials interfaces. Volume 6:Issue 20(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-08-28
• Subjects: biocompatible -- corrosion protection -- magnesium alloy -- nanoparticle conversion coating -- tea stain like; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201900899
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Magnesium alloys are biodegradable metals, but high corrosion speed and low histocompatibility after implantation still limit the application as biomedical implants. In this work, a bionic coating concept is put forward via mimicking a continuous "tea stain" formation process, using a layer‐by‐layer approach. Tannic acid (TA) incorporating Mg 2+ ions is used to form a chemical conversion coating on magnesium AZ31 alloy for enhanced corrosion protection and favorable biocompatibility. Thermal oxidation of TA, along with metal–phenol coordination and aggregation, forms an all nanoparticles stacked coating, which is crack‐free, homogeneous, more tight, and dense than the pure TA coating. In electrochemical corrosion tests, pH monitoring, and hydrogen evolution tests, the corrosion rate is effectively decreased for the TA/Mg protected AZ31, which is ascribed to the enriched phenol–metal complex and enhanced connections between the individual nanoparticles. With such green chemistry, the introduction of TA and incorporation of Mg 2+ synergistically endow the basic requirement of corrosion protection, without cytotoxicity to endothelial cells and with a safe hemolysis ratio. Additionally, this bionic coating effectively suppresses the inflammatory response to AZ31. These results convincingly demonstrate the effectiveness of using such coating as a biocompatible barrier for the potential application of biodegradable magnesium implants. Abstract : By mimicking tea stain, with the oxidation of tannic acid, metal‐phenol coordination and aggregation, an all‐nanoparticle and crack‐free protective coating is prepared on AZ31 substrate via layer‐by‐layer assembly. With such green chemistry, the enhanced interconnections among the polyphenols, metal‐phenol complex and nanoparticles make the coating a potent biocompatible barrier of corrosion protection for biodegradable magnesium alloys.