Biodegradable nanocomposite of glycerol citrate polyester and ultralong hydroxyapatite nanowires with improved mechanical properties and low acidity.

Glycerol citrate polyester based on the condensation of glycerol and citric acid has a great potential in biomedical applications owing to biocompatible monomers and biodegradation properties. However, the applications of glycerol citrate polyester are impaired by its poor mechanical properties and high acidity caused by citric acid produced in the degradation process. In this work, a new kind of nanocomposite has been developed using ultralong hydroxyapatite (HAP) nanowires as the "skeleton", and strongly bound glycerol citrate polyester as the "muscle". The ultralong HAP nanowires interweave with each other to form a three-dimensional nanoporous network, and glycerol citrate polyester is homogeneously distributed in the nanoporous network. Owing to the reinforcement of ultralong HAP nanowires, the mechanical properties of the as-prepared nanocomposite are significantly improved compared with the pure glycerol citrate polyester, and the tensile strength even reaches to the level of human cortical bones. Furthermore, the acidity of the aqueous solution after degradation is neutralized by the reaction between citric acid and ultralong HAP nanowires, and the pH value can be stabilized. The as-prepared nanocomposite can solve some problems of the pure glycerol citrate polyester, and shows promising applications in the biomedical field.