In vitro degradation study of polyanhydride copolymers / surface grafted hydroxyapatite composites for bone tissue application

Kuan Lin Ku, Lisbeth Grøndahl, Hui Dao, Ke Du, Simon Puttick, Po Liang Lai, Hui Peng, I. Ming Chu*, Andrew K. Whittaker

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

16 Scopus citations


Poly (1,6-bis- (p-carboxyphenoxy hexane)-co- (sebacic anhydride)) (PANH), is a polyanhydride copolymer which has good biocompatibility, and degrades to non-toxic products with a predictable rate of degradation. Nano-sized hydroxyapatite (HAP) is a well-known biomaterial which has been applied in bone regeneration due to its osteoconductivity. However, nano-sized HAP has poor colloidal stability which leads to agglomeration when incorporated into polymeric composites. In this work we describe the surface grafting of poly(ɛ-caprolactone) to HAP (PCL-gHAP) to improve the interfacial adhesion and dispersion of HAP particles in a PANH matrix to form a composite material. The use of scanning electron microscopy-backscattered electron (SEM-BSE) detector and the combination of focused ion beam (FIB)/ transmission electron microscopy (TEM) provided a powerful approach for observing the dispersion of HAP particles in the polymer matrix. We show that surface modification of HAP with PCL improved the homogeneity of the dispersion of HAP particles in the composites and affected the composite morphology during hydrolytic degradation. Composites with high HAP content displayed high compressive strength and a fast rate of degradation. The PCL-gHAP/PANH composites showed superior maintenance of mechanical properties compared with HAP/PANH composites during degradation. A preliminary in vivo study on rat calvaria repair, demonstrated the superior performance of PCL-gHAP/PANH composites. The results suggest that the newly developed PCL-gHAP/PANH composite materials have great potential of serving as a new substrate for bone tissue engineering.

Original languageEnglish
Pages (from-to)136-146
Number of pages11
JournalPolymer Degradation and Stability
StatePublished - 01 06 2017

Bibliographical note

Publisher Copyright:
© 2017


  • Grafted hydroxyapatite
  • In vitro degradation
  • Nanocomposite
  • Particle dispersion
  • Polyanhydride


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