A combined-modification method of carboxymethyl β-cyclodextrin and lignin for nano-hydroxyapatite to reinforce poly(lactide-co-glycolide) for bone materials.

Lignin is the second most abundant natural biomacromolecule. A new surface-modification for nano-hydroxyapatite (n-HA) by carboxymethyl β-cyclodextrin (CM-β-CD) and lignin and its reinforce effect for poly(lactide-co-glycolide) (PLGA) were investigated by Fourier transformation infrared (FTIR), X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), dispersion images, the tensile tests, scanning electron microscope (SEM), differential scanning calorimeter (DSC) and polarized optical microscopy (POM), compared to the singled-modification of CM-β-CD or lignin. The results showed that the appropriate combined-modified n-HA displayed excellent synergistic effects for increasing the dispersion, yielding good interfacial bonding between n-HA with PLGA matrix. The tensile strength of the composite was still 14.53% higher than that of PLGA, for a n-HA addition amount of 15 wt%, which was significantly better than that for the singled-modified n-HA. Additionally, in vitro degradation behavior was evaluated by soaking in simulated body fluid (SBF), and their cell response was carried out by interaction tests with bone mesenchymal stem cells. The results indicated that the combined-modification method promoted good degradation behavior and apatite deposition, as well as excellent cell biocompatibility. This study may offer an important guidance to obtain PLGA-based composites reinforced by surface-modified n-HA as bone materials.