Nanocomposites of cross-linking polyanhydrides and hydroxyapatite needles: mechanical and degradable properties

Three methacrylated anhydride monomers of citric acid (MCA), sebacic acid (MSA) and 1,4-bis(carboxyphenoxy) butane (MCPB) were utilized to prepare biodegradable nanocomposites with homogenously distributed hydroxyapatite (HAp) nanoneedles by in situ photopolymerization, where the needle-like HAp particles were homogenously dispersed in cross-linked polyanhydride network at nanoscale. The incorporation of HAp cannot only dramatically increase the compressive properties of the nanocomposites but also play an important role in decreasing the cumulative mass loss and in increasing the mechanical integrity of nanocomposites during the degradation. The results showed that it was possible to prepare such HAp/polyanhydride nanocomposite, with proper mechanical strength and controlled degradable rate, by adjusting the content of HAp in the polyanhydrides and by changing the compositions in the cross-linking network to meet the rehabilitation need of different fracture bones in human body, both in mechanical properties and in the biodegradable rate. (C) 2004 Elsevier B.V. All rights reserved.