Bone tissue exhibits inherent regenerative capabilities. Nevertheless, the adjunct of specialized biomaterials often proves beneficial, if not essential, for enhancing this healing process. Among these, bone cements stand out as biofunctional materials. Magnesium phosphate cements (MPCs) are distinguished by rapid setting, high initial mechanical strength, advantageous resorption, and osteogenic properties. Yet, challenges such as pronounced brittleness, paste leachability, and injection difficulties persist. Addressing these issues, this study introduces a novel dual-setting MPC-based cement formula modified with poly(2-hydroxyethyl methacrylate) (HEMA), aiming to enhance performance and applicability.

The formulation comprised an MPC powder component of tri-magnesium phosphate combined with di-ammonium hydrogen phosphate at a 4:1 mass ratio, alongside liquid components of 2-hydroxyethyl methacrylate solutions. HEMA polymerization was triggered by APS+TEMED, starting hydrogel formation after premixing (2-4 min). Specimen preparation involved mixing the components at a 2.5 g/mL powder-to-liquid ratio to achieve a paste, which was subsequently cast into molds and cured (24h, 37°C, >90% humidity). Evaluations comprised setting time, SEM microstructure, XRD and FTIR analyses, mechanical strengths, porosity, and degradation rate. Further, cytocompatibility was assessed using human osteoblasts.

The integration of a hydrogel component was pivotal in modulating the cement's functional characteristics. Notably, the concentration of HEMA and the duration of premixing markedly influenced hydrogel agglomerate formation within the cement matrix. Enhanced mechanical strength was associated with extended premix times and HEMA concentrations. Conversely, shorter premix durations facilitated more rapid and efficient matrix degradation. Cytotoxic effects observed in cultured osteoblasts were attributed to the application of TEMED as a catalyst in the polymerization process. Despite the achievement of desirable functional and mechanical properties, further investigations should explore alternative hydrogel additives or modifications to the HEMA polymerization methodology.

Acknowledgment: This research was partially supported by the Gdańsk University of Technology by the DEC-3/2022/IDUB /III.4.3/Pu grant under the PLUTONIUM 'Excellence Initiative – Research University' program.