Polymethyl methacrylate (
PMMA)
bone cement is widely used to relieve
pain caused by metastatic bone
tumors. We previously found that
PMMA bone cement containing 15 mass% or more of TiO2 showed good
apatite-forming ability, and 25 mass% or more of Fe3O4 generated sufficient heat for
hyperthermia under an alternating current (AC) magnetic field. In this study, the cytocompatibility of
PMMA bone cement with Fe3O4:TiO2 weight ratios of 25:15 (F25T15-3/2-42) and 30:15 (F30T15-3/2-42) was evaluated using osteoblastic cells (MC3T3-E1). The proliferation and differentiation of MC3T3-E1 cells were suppressed for F25T15-3/2-42 and F30T15-3/2-42 compared to
PMMA bone cement without Fe3O4 and TiO2 (F0T0-3/2-42). The release of methyl
methacrylate (MMA) monomers from F25T15-3/2-42 and F30T15-3/2-42 at 7 days was about 33 and 50 times higher than that from F0T0-3/2-42, respectively. The remarkable release of MMA monomers from F25T15-3/2-42 and F30T15-3/2-42 may be responsible for the suppressed proliferation and differentiation of MC3T3-E1 cells. The release of MMA monomers was not reduced when the MMA/
PMMA weight ratio was decreased from 3/2 to 1/1, however, it was significantly reduced by increasing the content of
benzoyl peroxide (BPO) and
N, N-dimethyl-p-toluidine (
DMPT) to 8 and 4 mass% against MMA, respectively. Proliferation and differentiation of MC3T3-E1 cells on
PMMA-type cements containing Fe3O4 and TiO2 with increased BPO and
DMPT contents need to be investigated in the future; however, our findings will be useful for designing
PMMA cements for the hyperthermic treatment of metastatic bone
tumors.