A study on mechanical performance and bioactivity of PMMA-HA-graphene bone cements

In this work, PMMA/HA/graphene bone cements with clinically relevant compositions were fabricated and evaluated. Four formulations containing 0, 1, 2, and 3 wt% graphene (with 85 wt% PMMA and 15 wt% HA) were prepared for orthopedic and dental applications. The cements were characterized by FE‑SEM/EDX, porosity and water uptake measurements, and mechanical tests (tensile and Charpy impact). Bioactivity and pH evolution were studied in simulated body fluid (SBF), and water absorption was determined in phosphate-buffered saline (PBS). The 2 wt% graphene formulation showed the best overall performance, with an impact strength of 12.48 kJ/m², compatible with ASTM F451 expectations, and a Young’s modulus of 1.97 GPa, within the range of cancellous bone. FE‑SEM/EDX confirmed enhanced apatite formation on graphene‑containing samples, and SBF tests indicated a stable, non‑cytotoxic pH of about 6.6–6.7. This composition also presented a porous microstructure with interconnected pores of roughly 45–65%, which can support fluid transport and bone ingrowth. Taken together, the results suggest that an intermediate graphene loading of 2 wt% provides a useful balance between mechanical integrity and bioactivity in PMMA/HA bone cements for orthopedic use.