Preparation of macroporous poly (2-hydroxyethyl) methacrylate with interconnected porosity

The design of a macromolecular bone graft with interconnected macroporosity represents a major challenge in the field of orthopaedic biomaterials. Such a synthetic graft would combine the biocompatibility and the biomechanical behavior with a micro-architecture allowing the osteoconduction through the colonization of the implant by bony cells and blood vessels. Macroporous pHEMA blocks were obtained by polymerizing 2-hydroxyethyl methacrylate around polystyrene beads of four diameters (600, 800, 1200, 1600 mum). X-ray microtomography (microCT) and scanning electron microscopy were used to evaluate the porosity and the interconnectivity. Porosity did not differ whatever the size of the beads used as porogen. Porosity was in the range of 58-66%, close to that of calf trabecular bone, a material used for preparing bone xenografts. Chromatographic analysis was performed in order to check the presence of residual monomer. The biomechanical characteristics of these porous materials were measured in compression and appeared close to those of calf bone used for xenografts.