Study on the surface-modification of nano-hydroxyapatite with lignin and the corresponding nanocomposite with poly (lactide-co-glycolide)

To obtain nano-hydroxyapatite/poly(lactide-co-glycolide) (n-HA/PLGA) nanocomposite with superior mechanical properties, here, lignin was chosen to surface-modify for n-HA through co-precipitation method. The different reaction conditions of reaction time, phosphorus source, and the lignin addition amount were studied by fourier transformation infrared spectra, X-ray diffraction, the intuitionistic dispersion experiment, transmission electron microscope and thermal gravimetric analysis. The reaction mechanism and the best appropriate reaction condition were obtained. More importantly, the results of electromechanical universal tester, scanning electron microscope, differential scanning calorimetric analyzer, polarized optical microscopy and dynamic mechanical analysis confirmed that the obtained n-HA could greatly increase the mechanical strength of PLGA, owing to the excellent dispersion and promotion crystallization effect. Moreover, in vitro cell culture experimental results indicated that the n-HA surface-modified by lignin was favorable to improve the cell biocompatibility of PLGA. The study suggested that the introduction of lignin was a novel method to acquire a highly dispersed n-HA, which would provide a new idea to achieve the n-HA/PLGA nanocomposite as bone materials in future, and it would pave the way towards a new application of lignin in biomedical field.