HEMA-Modified Expandable P(MMA-AA) Bone Cement with Dual Water Absorption Networks

Although the shrinkage of polymethyl methacrylate (PMMA) bone cement has been tackled by the poly(methyl methacrylate-co-acrylic acid) [P(MMA-AA)] bone cement due to the expandable P(MMA-AA) copolymer in the solid phase, the hydrophobicity of PMMA and its solidification restrict simulated body fluid (SBF) diffusion and expansion properties. In this research, hydroxyethyl methacrylate (HEMA)-modified P(MMA-AA) bone cement (HMBC) is obtained by introducing HEMA into the liquid phase of P(MMA-AA) bone cement. It is assumed that the dual water absorption networks can promote the SBF absorption capacity, thus resulting in the increased expansion behavior. The results demonstrate that the introduction of HEMA improves the hydrophilicity of the bulk. SBF absorption efficiency and swelling efficiency are promoted in the primary step of expansion. The porous structure of HMBC contributes to the increased SBF absorption and swelling in the second step of expansion behavior. Meanwhile, the remarkable absorption ratio and expansion ratio reach 88.5% and 97.4%, respectively. Furthermore, enhanced biocompatibility and osteogenesis activity provide HMBC as a promising biomaterial in the clinical setting.