Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China; Medical Research Center, Department of Orthopedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, China.
State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China.
Acta Biomater. 2022 Oct 15;152:575-592. doi: 10.1016/j.actbio.2022.08.066. Epub 2022 Sep 5.
Implant-associated infections (IAI) and osseointegration disorders are the most common complications in orthopedics. Studies have shown that neutrophils surrounding implants play a vital role in regulating these complications. Although magnesium (Mg) and its alloys are considered promising biodegradable bone implants, their role in neutrophil-mediated antibacteria has not yet been examined. Considering the rapid corrosion of Mg, it is necessary to develop methods to inhibit its corrosion. To solve these issues, a zinc-doped ferric oxyhydroxide nano-layer modified plasma electrolytic oxidation (PEO)-coated Mg alloy (PEO-FeZn) was developed in this study, and its antibacterial, immune anti-infective, and osteogenic ability were systematically evaluated. The results showed that PEO-FeZn nano-layer enhanced the corrosion resistance, biocompatibility, bactericidal activity, and osteoblastic differentiation activity of the Mg alloy. Moreover, PEO-FeZn nano-layer inhibited immune evasion-related gene expression and contributed to the formation of neutrophil extracellular traps (NETs) by activating the extracellular release of DNA fibers and granule proteins, and thereby suppressing bacterial invasion and promoting osseointegration in vivo in Staphylococcus aureus (S. aureus)-infected rat femurs. Overall, the findings of this study could serve as a reference for the fabrication of highly biocompatible and corrosion resistant Mg alloys to address the challenges of IAI and osseointegration disorders. STATEMENT OF SIGNIFICANCE: The widely used metallic biomaterials usually come with the risk of IAI. As the first responder around the biomaterials, neutrophils could form NETs to defense against microorganism and promote tissue remodeling. Therefore, biomaterials addressing antibacterial and neutrophils-modulatory strategies are highly necessary in reducing IAI. To solve these issues, we grew PEO-FeZn nano-layers in situ on Mg alloy using a simple and green technique. The nano-layer not only enhanced the corrosion resistance and biocompatibility of Mg alloy, but also elevated the antibacterial and osteogenesis capability. Moreover, nano-layer contributed to NETs formation, thereby suppressing bacterial invasion and even promoting osseointegration in S.aureus-infected femurs. Accordingly, this functionalized multilayer coating with antibacterial immunity represents a novel therapeutic strategy for IAI and weak osseointegration.
植入物相关感染(IAI)和骨整合障碍是骨科中最常见的并发症。研究表明,围绕植入物的中性粒细胞在调节这些并发症方面起着至关重要的作用。尽管镁(Mg)及其合金被认为是有前途的可生物降解骨植入物,但它们在中性粒细胞介导的抗菌作用方面尚未得到检验。考虑到镁的快速腐蚀,有必要开发抑制其腐蚀的方法。为了解决这些问题,本研究开发了一种锌掺杂的铁氢氧化物纳米层修饰的等离子体电解氧化(PEO)涂层镁合金(PEO-FeZn),并系统评估了其抗菌、免疫抗感染和成骨能力。结果表明,PEO-FeZn 纳米层增强了镁合金的耐腐蚀性、生物相容性、杀菌活性和成骨细胞分化活性。此外,PEO-FeZn 纳米层通过激活细胞外 DNA 纤维和颗粒蛋白的释放,抑制免疫逃避相关基因表达,形成中性粒细胞胞外陷阱(NETs),从而抑制金黄色葡萄球菌(S. aureus)感染大鼠股骨中的细菌入侵,促进体内骨整合。总的来说,本研究结果可为制备高生物相容性和耐腐蚀性的镁合金提供参考,以解决 IAI 和骨整合障碍的挑战。