The effect of the prefrozen process on properties of a chitosan/hydroxyapatite/poly(methyl methacrylate) composite prepared by freeze drying method used for bone tissue engineering

Abstract

A chitosan–hydroxyapatite (CS–HA) scaffold reinforced by poly(methyl methacrylate) (PMMA) with good mechanical strength was fabricated. Chitosan–hydroxyapatite scaffolds supplemented with poly(methyl methacrylate) were fabricated using the freeze drying technology and free radical polymerization. Possible applications of the prepared CS–HA/PMMA scaffolds in tissue engineering were tested. The effect of the freeze drying process and chitosan concentration on the properties of the scaffolds were also investigated. The morphology of the CS–HA scaffolds was examined using scanning electron microscopy (SEM). The thermal property of the complex scaffolds was examined using thermogravimetry analysis (TGA). The mechanical property of the bone composites was characterized using an Instron 4505 mechanical tester. Indirect in vitro cytotoxicity tests showed that the bone composite extracts had no significant effect on cell viability. Moreover, in vitro cytocompatibility tests also exhibited a cell population and spreading tendency, which suggest that the CS–HA/PMMA scaffolds were non-toxic to L929 cells. All the results indicated that not only the freeze drying method had significant influence on the properties of the complex scaffolds, but also chitosan concentration had significant influence on the properties of the complex scaffolds. The proposed method could be used to fabricate CS–HA/PMMA bone composites by freeze drying and free radical polymerization, and the fabricated bone composites might have potential applications in the bone tissue engineering scaffold field.