Crosslinked Poly(methyl Methacrylate) Bone Cement Reinforced with a Bioactive Calcium-Olsalazine Metal-Organic...

The applications of polymethyl methacrylate (PMMA) bone cement (BC) in orthopedic surgeries have exhibited two major drawbacks: inferior mechanical properties and inferior bioactivities. Herein, we describe the introduction of Ca-olsalazine metal-organic framework (MOF) materials to advance PMMA BC for the first time. The Ca-olsalazine MOFs could be directly grown on the surfaces of PMMA beads via a hydrothermal approach, and then after the double-phase polymerization reaction of PMMA, they were facilely incorporated into the PMMA BCs. Furthermore, with the Ca-olsalazine MOFs offering the amine group to react with citric acid, the amido bonding-induced crosslinking could form during the BC formation process. These treatments remarkably enhanced the mechanical properties of the PMMA BCs, including the flexural strength from 136 to 192 MPa (41.1% increase) and the compression strength from 77 to 99 MPa (28.6% increase). Moreover, the resultant crosslinked Ca-olsalazine MOF- PMMA (c/Ca-MOF/PMMA) BCs induced the deposition of apatite via immersion in simulated body fluid (SBF). In addition, the c/Ca-MOF/PMMA BCs had good cytocompatibility, evaluated using NIH3T3 cells as model cells. Finally, the c/Ca-MOF/PMMA BCs were implanted subcutaneously inside SD mice for three weeks. The obtained results revealed the promotion of the host repair response. This study shows the promising potential of Ca-olsalazine bioactive MOFs in developing high-performance PMMA based BCs.