Preparation of epoxy-SiO₂ hybrid sol-gel material for bone cement

An organic-inorganic hybrid material, epoxy-SiO₂, was prepared by incorporating epoxy structure units covalently into a SiO₂ glass network via the sol-gel approach. The precursor was obtained by the reaction of diglycidyl ether of bisphenol A (DGEBA) with 3-aminopropyl trimethoxysilane (APTS). The precursor was then hydrolyzed and co-condensated with tetraethyl orthosilicate (TEOS) in tetrahydrofuran (THF) at room temperature to yield epoxy-SiO₂ hybrid sol-gel material having a 50 wt % SiO₂ content. Thermal properties of the hybrid material were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The hybrid sol-gel material epoxy-SiO₂ was the solid, powder component of bone cement. The liquid component contains bis-phenol-A glycidyl methacrylate (Bis-GMA), triethyleneglycol dimethacrylate (TEGDMA), and methyl methacrylate (MMA) with 25, 55, and 20 vol %, respectively. We discuss the comparison between the new epoxy-SiO₂ bone cement and the commercial Simplex® P bone cement. Mechanical properties such as Young's modulus, compressive strength, hardness, and impact strength of the new epoxy-SiO ₂ bone cement exceeded those of Simplex® P bone cement. The tensile and bending strengths of the new epoxy-SiO₂ bone cement were approximately the same as those of Simplex® P bone cement. In order to evaluate the biocompatibility of the new bone cement, an MTT test and optical microscopy were conducted in cell culture. Results indicated that the new epoxy-SiO₂ bone cement exhibits very low cytotoxicity compared with Simplex® P bone cement.