RETRACTED: Magnesium calcium alloys/mineralized collagen composites mediating macrophage polarization to promote bone repair

Abstract

Magnesium-based composites are a focal point in biomaterials research. However, the rapid degradation rate of magnesium alloys does not align with the healing time of bone tissue. Additionally, the host reaction caused by magnesium implantation hampers its full osteogenic potential. To maintain an appropriate microenvironment, it is essential to enhance both the corrosion resistance and osteogenic activity of the magnesium matrix. In this study, a composite scaffold composed of mineralized collagen (nHAC) and magnesium alloy was utilized to investigate the regulatory effect of nHAC on RAW264.7 macrophages and evaluate its impact on mouse bone marrow mesenchymal stem cells (mBMSCs) in terms of osteogenesis, immune response, and macrophage-induced osteogenic differentiation. The findings revealed that Mg-Ca/nHAC biomaterials primarily induced osteogenic differentiation through M2 polarization of macrophages, while Mg2+/Col I stimulated the integrin alpha2beta1-FAK-ERK1/2 pathway to promote bone formation. Cells treated with Mg-Ca/nHAC exhibited extensive spreading and flattening towards the surrounding area, facilitated by broad and abundant pseudopodia that firmly adhered them to the material surface and promoted growth as well as pseudopodia formation. These composite scaffolds based on prepared magnesium alloys hold significant potential for wide-ranging applications in bone tissue engineering.