Department of Orthopaedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200233, China.
State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China.
Nanoscale. 2017 Jan 5;9(2):875-892. doi: 10.1039/c6nr07729c.
Biomaterial-related bacterial infections cause patient suffering, mortality and extended periods of hospitalization, imposing a substantial burden on medical systems. In this context, understanding of nanomaterials-bacteria-cells interactions is of both fundamental and clinical significance. Herein, nano-MgF films were deposited on titanium substrate via magnetron sputtering. Using this platform, the antibacterial behavior and mechanism of the nano-MgF films were investigated in vitro and in vivo. It was found that, for S. aureus (CA-MRSA, USA300) and S. epidermidis (RP62A), the nano-MgF films possessed excellent anti-biofilm activity, but poor anti-planktonic bacteria activity in vitro. Nevertheless, both the traditional SD rat osteomyelitis model and the novel stably luminescent mouse infection model demonstrated that nano-MgF films exerted superior anti-infection effect in vivo, which cannot be completely explained by the antibacterial activity of the nanomaterial itself. Further, using polymorphonuclear leukocytes (PMNs), the critical immune cells of innate immunity, a complementary investigation of MgF-bacteria-PMNs co-culturing revealed that the nano-MgF films improved the antibacterial effect of PMNs through enhancing their phagocytosis and stability. To our knowledge, this is the first time of exploring the antimicrobial mechanism of nano-MgF from the perspective of innate immunity both in vitro and in vivo. Based on the research results, a plausible mechanism is put forward for the predominant antibacterial effect of nano-MgFin vivo, which may originate from the indirect immune enhancement effect of nano-MgF films. In summary, this study of surface antibacterial design using MgF nanolayer is a meaningful attempt, which can promote the host innate immune response to bacterial pathogens. This may give us a new understanding towards the antibacterial behavior and mechanism of nano-MgF films and pave the way towards their clinical applications.
生物材料相关的细菌感染会导致患者痛苦、死亡和延长住院时间，给医疗系统带来巨大负担。在这种情况下，纳米材料-细菌-细胞相互作用的理解具有基础和临床意义。在此，通过磁控溅射在钛基底上沉积了纳米 MgF 薄膜。利用该平台，体外和体内研究了纳米 MgF 薄膜的抗菌行为和机制。结果发现，对于金黄色葡萄球菌（CA-MRSA，美国 300 型）和表皮葡萄球菌（RP62A），纳米 MgF 薄膜具有优异的抗生物膜活性，但体外抗浮游菌活性差。然而，传统的 SD 大鼠骨髓炎模型和新型稳定发光的小鼠感染模型均表明，纳米 MgF 薄膜在体内具有优异的抗感染效果，这不能完全用纳米材料本身的抗菌活性来解释。此外，利用多形核白细胞（PMN）作为先天免疫的关键免疫细胞，对 MgF-细菌-PMN 共培养进行了补充研究，结果表明纳米 MgF 薄膜通过增强 PMN 的吞噬作用和稳定性来提高其抗菌效果。据我们所知，这是首次从先天免疫的角度，在体外和体内探索纳米 MgF 的抗菌机制。基于研究结果，提出了一个合理的机制来解释纳米 MgF 在体内的主要抗菌作用，这可能源于纳米 MgF 薄膜的间接免疫增强作用。总之，这项使用 MgF 纳米层进行表面抗菌设计的研究是一次有意义的尝试，可以促进宿主对细菌病原体的先天免疫反应。这可能为我们提供一个新的认识，即纳米 MgF 薄膜的抗菌行为和机制，并为其临床应用铺平道路。
