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Updated: Sep 25, 2025
Polarization and Characterization of M1 and M2 Human Monocyte-Derived Macrophages on Implant Surfaces
Published on: December 6, 2024
Sequential activation of M1 and M2 phenotypes in macrophages by Mg degradation from Ti-Mg alloy for enhanced
Luxin Liang1,2, Deye Song2, Kai Wu3
1State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083, People's Republic of China.
Background:
Even though the modulatory effects of Magnisum (Mg) and its alloys on bone-healing cells have been widely investigated during the last two decades, relatively limited attention has been paid on their inflammation-modulatory properties. Understanding the activation process of macrophages in response to the dynamic degradation process of Mg as well as the relationship between macrophage phenotypes and their osteogenic potential is critical for the design and development of advanced Mg-based or Mg-incorporated biomaterials.
Methods:
In this work, a Ti-0.625 Mg (wt.%) alloy fabricated by mechanical alloying (MA) and subsequent spark plasma sintering (SPS) was employed as a material model to explore the inflammatory response and osteogenic performance in vitro and in vivo by taking pure Ti as the control. The data analysis was performed following Student's t-test.
Results:
The results revealed that the macrophages grown on the Ti-0.625 Mg alloy underwent sequential activation of M1 and M2 phenotypes during a culture period of 5 days. The initially increased environmental pH (~ 8.03) was responsible for the activation of M1 macrophages, while accumulated Mg2+ within cells contributed to the lateral M2 phenotype activation. Both M1 and M2 macrophages promoted osteoblast-like SaOS-2 cell maturation. In vivo experiment further showed the better anti-inflammatory response, regenerative potentiality and thinner fibrous tissue layer for the Ti-0.625 Mg alloy than pure Ti.
Conclusion:
The results highlighted the roles of Mg degradation in the Ti-0.625 Mg alloy on the sequential activation of macrophage phenotypes and the importance of modulating M1-to-M2 transition in macrophage phenotypes for the design and development of inflammation-modulatory biomaterials.
Insights
Magnesium alloys modulate macrophage responses, promoting bone healing. Sequential M1 and M2 macrophage activation by degrading magnesium alloys enhances osteogenic potential and reduces inflammation, crucial for biomaterial design.
Area of Science:
- Biomaterials Science
- Immunology
- Regenerative Medicine
Background:
- While magnesium (Mg) and its alloys' effects on bone healing are known, their inflammation-modulatory properties require further investigation.
- Understanding macrophage activation by Mg degradation is key for developing advanced Mg-based biomaterials.
Purpose of the Study:
- To explore the inflammatory response and osteogenic performance of a Ti-0.625Mg alloy.
- To investigate the relationship between macrophage phenotypes and osteogenic potential in response to Mg degradation.
Main Methods:
- Fabrication of Ti-0.625Mg alloy using mechanical alloying (MA) and spark plasma sintering (SPS).
- In vitro and in vivo evaluation of inflammatory response and osteogenic performance, using pure Ti as a control.
- Macrophage phenotype analysis (M1/M2) and SaOS-2 cell maturation assessment.
Main Results:
- Ti-0.625Mg alloy induced sequential M1 and M2 macrophage activation over 5 days.
- Increased environmental pH activated M1, while intracellular Mg2+ promoted M2 phenotype.
- Both M1 and M2 macrophages enhanced osteoblast-like SaOS-2 cell maturation; in vivo studies showed reduced inflammation and improved regeneration for Ti-0.625Mg.
Conclusions:
- Magnesium degradation in Ti-0.625Mg alloys drives sequential macrophage phenotype activation.
- Modulating the M1-to-M2 transition is crucial for designing inflammation-modulatory biomaterials.
- Ti-0.625Mg alloys demonstrate potential for enhanced bone regeneration and reduced fibrous encapsulation.
