Characterization and in vitro and in vivo assessment of poly(butylene adipate-co-terephthalate)/nano-hydroxyapatite composites as scaffolds for bone tissue engineering

The polyester for bone tissue engineering is produced using different concentrations of hydroxyapatite. Poly(butylene adipate-co-terephthalate) (PBAT) solutions containing different concentrations of nano-hydroxyapatite (nHAp) (1, 2, 3, 4, 5 and 6% wt) were evaluated to assess their potential to produce scaffolds via electrospinning. The characteristics of these solutions were evaluated using surface tension analysis. Different solutions were electrospun and characterized using scanning electron microscopy, X-ray diffractometry (XRD), infrared spectroscopy (FTIR), and differential scanning calorimetry analysis. In vitro and in vivo experiments were performed using MG-63 osteoblast cells and male Wistar rats. The MTT assay was used to evaluate the cytotoxicity of scaffolds. Microtomography and a three-point bend test were used to analyze parameters of bone neoformation 4 weeks after implantation. We observed a requirement for solutions containing nHAp to reach chemical stability to produce ultrathin fibers. FTIR and XRD data demonstrated the presence of carbonate and phosphate groups, and thermal analysis showed a reduction in crystallinity of the nanocomposites when the concentration of nHAp was increased. None of the scaffolds analyzed demonstrated cytotoxicity when compared to controls. All of the PBAT/nHAp scaffolds analyzed promoted bone repair; however, a solution of PBAT with 3% nHAp improved bone volume, force, and stiffness when compared to controls.