Melatonin and Calcium Phosphate Crystal-loaded Poly(L-lactic acid) Porous Microspheres Reprogram Macrophages to Improve Bone Repair

The bone immune microenvironment can influence the occurrence and progression of bone defects. To date, research on promoting macrophage M2 polarization to improve bone injury repair has been insufficient. In this study, we designed an injectable poly(L-lactic acid) (PLLA) porous microsphere that forms calcium phosphate crystals on its surface by binding to melatonin, followed by bionanomimetic mineralization