Thein vitrobiocompatibility and macrophage phagocytosis of Mg₁₇Al₁₂phase in Mg-Al-Zn alloys

Abstract

Mg alloys are gaining interest for applications as biodegradable medical implant, including Mg-Al-Zn series alloys with good combination of mechanical properties and reasonable corrosion resistance. However, whether the existence of second phase particles in the alloys exerts influence on the biocompatibility is still not clear. A deeper understanding of how the particles regulate specific biological responses is becoming a crucial requirement for their subsequent biomedical application. In this work, the in vitro biocompatibility of Mg17Al12 as a common second phase in biodegradable Mg-Al-Zn alloys was investigated via hemolysis, cytotoxicity, cell proliferation, and cell adhesion tests. Moreover, osteogenic differentiation was evaluated by the extracellular matrix mineralization assay. The Mg17Al12 particles were also prepared to simulate the real situation of second phase in the in vivo environment in order to estimate the cellular response in macrophages to the Mg17Al12 particles. The experimental results indicated that no hemolysis was found and an excellent cytocompatibility was also proved for the Mg17Al12 second phase when co-cultured with L929 cells, MC3T3-E1 cells and BMSCs. Macrophage phagocytosis co-culture test revealed that Mg17Al12 particles exerted no harmful effect on RAW264.7 macrophages and could be phagocytized by the RAW264.7 cells. Furthermore, the possible inflammatory reaction and metabolic way for Mg17Al12 phase were also discussed in detail.

A C1q domain containing protein from Crassostrea gigas serves as pattern recognition receptor and opsonin with high binding affinity to LPS

“…Different from vertebrate C1q, it might be impossible for CgC1qDC-1 to form polymer structure and activate downstream complement pathway, suggesting that CgC1qDC-1 mainly serve as a PRR to trigger the immune response of oyster against invading pathogens. A large quantity of PRRs in C. gigas, including C1qDC proteins, have been proved to involve in innate immune response, such as pathogen recognition and clearance [37,38]. Gram-negative bacteria, which engage LPS as the dominant PAMPs, are the main source of C. gigas pathogens.…”

Biodegradable Magnesium Alloys Developed as Bone Repair Materials: A Review

“…Mg 17 Al 12 second phase did not induce hemolysis and had excellent cytocompatibility. Mg 17 Al 12 particles are processed in endolysosomal compartments and lysosomes play a major role in digesting Mg 17 Al 12 particles [ 107 ].…”

Effects of Intermetallic Microstructure on Degradation of Mg-5Nd Alloy

“…where Dm is the weight loss in grams, A is the surface area of samples immersed in medium in cm 2 , t is the immersion time in hours, q is the density of samples in g/ cm 3 and DR is the degradation rate in mm/y. The actual density of the as-extruded Mg-5Nd was measured according to Archimedes' principle using 100 pct ethanol as a fluid and a balance (Sartorius LA 230S analytical balance, Sartorius Corporate Administration GmbH, Go¨ttingen, Germany) for weighting.…”

“…Many of the current developed biodegradable magnesium alloys contain intermetallics. [1][2][3][4][5][6][7] When these alloys are immersed in corrosive media, the intermetallic compounds can couple with a-Mg to result in possible galvanic corrosion. [8][9][10] The corrosion resistance of Mg alloys is closely related with the distribution of these intermetallic compounds.…”