Osteogenic Induction and Anti-inflammatory Effects of Calcium-Chlorogenic Acid Nanoparticles Remodel the Osteoimmunology Microenvironment for Accelerating Bone Repair.

Successful bone regeneration requires the close cooperation between bone marrow mesenchymal stem cells (BMSCs) and macrophages, but the low osteogenic differentiation efficiency of stem cells and the excessive inflammatory response of immune cells hinder the development of the bone repair. It is necessary to develop a strategy that simultaneously regulates the osteogenic differentiation of BMSCs and the anti-inflammatory polarization of macrophages for accelerating the bone regeneration. Herein, calcium-chlorogenic acid nanoparticles (Ca-CGA NPs) were synthesized by combining the small molecular of chlorogenic acid (CGA) with Ca2+. Ca-CGA NPs internalized by cells could be dissolved to release free CGA and Ca2+ under low pH conditions in lysosomes. In vitro results demonstrated that Ca-CGA NPs could not only enhance the osteogenic differentiation of BMSCs, but also promote the phenotype transformation of macrophages from M1 to M2. Furthermore, in vivo experiments confirmed that Ca-CGA NPs treatment facilitated the recovery of rat skull defect model through both the osteoinduction and immunomodulation. This study develops a new Ca-CGA NPs-based strategy to induce the differentiation of BMSCs into osteoblasts and the polarization of macrophages into M2 phenotype, which is promising for accelerating bone repair. This article is protected by copyright. All rights reserved.