Clinical PMMA bone cement enhanced by interpenetrating chitosan microgel: Synergistic toughness and bioactivity

Polymethyl methacrylate (PMMA) bone cement has been widely utilized in clinical orthopedics. However, several challenges have arisen with its long-term application, including inherent brittleness and limited bioactivity. To overcome these limitations, this study explored the incorporation of chitosan microgels into PMMA via in situ polymerization to enhance its toughness and bioactivity. Remarkably, the addition of 0.5 wt% chitosan microgel significantly improved the mechanical performance of PMMA, yielding a 150% increase in elongation at break and a 240% enhancement in tensile toughness. These enhancements were supported by rheological analyses and SEM observations, which revealed the formation of an interpenetrating polymer network (IPN) between PMMA and the chitosan microgels. This network effectively restricted the segmental mobility of PMMA chains and facilitated energy dissipation under mechanical stress, thereby improving overall toughness. When extended to PMMA-based bone cement, the chitosan microgel-modified composites exhibited further mechanical improvements, including enhanced bone adhesion and fatigue resistance. In vivo biological evaluations confirmed that chitosan microgels accelerated bone regeneration and increased bone mineral density (BMD). Collectively, these findings provide a promising foundation for the development of strategy as a facile route toward the development of next-generation, multifunctional PMMA-based bone cements.