Mg(OH)₂ nanosheets on Ti with immunomodulatory function for orthopedic applications

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cell Biology

Background:

• Macrophages are crucial for osteogenesis.
• Nano-topography and bioactive ions can improve bone healing.
• The combined effect of nano-structure and ion release on macrophages and subsequent osteogenesis/angiogenesis is understudied.

Purpose of the Study:

• To investigate the impact of nano-Mg(OH)2 films on titanium on macrophage polarization.
• To evaluate the influence of these films on osteogenesis and angiogenesis in vivo and in vitro.
• To assess the potential of nano-Mg(OH)2 coated titanium for orthopedic applications.

Main Methods:

• Hydrothermal synthesis of Mg(OH)2 nano-sheet films on titanium.
• In vitro studies using bone marrow-derived macrophages (BMDMs) with PCR, Western blot, and flow cytometry.
• In vivo air-pouch model implantation.
• Collection of conditioned media for assessing osteogenic and angiogenic potential.

Main Results:

• Nano-Mg(OH)2 films promoted M2 macrophage polarization.
• In vivo studies showed reduced inflammation and thinner fibrous layers compared to untreated titanium.
• Conditioned media enhanced osteogenesis in bone marrow stem cells and angiogenesis in endothelial cells.

Conclusions:

• Nano-Mg(OH)2 films on titanium modulate macrophage polarization towards a pro-healing M2 phenotype.
• This modulation leads to reduced inflammation and improved osteogenesis and angiogenesis.
• Nano-Mg(OH)2 coated titanium shows promise for orthopedic applications due to its favorable biological response.