Advancements in biofunctional dual-setting bone cements: The potential of pHEMA hydrogel enhancement for magnesium phosphate cement

Bone regeneration capabilities are inherent to skeletal tissue. However, the integration of specialized biomaterials is frequently necessary, enhancing and sometimes being crucial to the bone healing process. Bone cements are particularly notable within this context as they exhibit biofunctionality. Specifically, magnesium phosphate cement (MPC) is recognized for its quick setting, high mechanical strength, and osteogenic benefits, despite issues like brittleness and injection complications. This study presents a novel MPC-based cement enhanced with poly(2-hydroxyethyl methacrylate) (HEMA) hydrogel, aimed at overcoming these limitations.

The novel cement formulation includes a powder mix of tri-magnesium phosphate and di-ammonium hydrogen phosphate at a 4:1 ratio, combined with HEMA solutions (15-25%). Polymerization, initiated by APS/TEMED, with different premixing times, facilitates hydrogel formation. Specimen preparation involved mixing the above components at a 2.5 g/mL ratio, subsequently putting the obtained paste into molds, and curing them (24h, 37°C, >90% humidity). Evaluations covered setting time, SEM microstructure, XRD and FTIR analyses, mechanical strengths, porosity, degradation rate, and cytocompatibility with human osteoblasts.

Key findings indicate that incorporating HEMA hydrogel markedly impacts the primary properties of MPC. Specifically, alterations in the concentration of HEMA and the duration of premixing significantly influence the creation of hydrogel aggregates within the cement matrix, contributing to enhanced mechanical properties and facilitating controlled degradation. Importantly, although the modified cement demonstrated advantageous functional and mechanical properties, future research should prioritize exploring alternative hydrogel formulations or modifications to the HEMA polymerization process.

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.