Biomedical applications of polyhydroxyalkanoates, an overview of animal testing and in vivo responses

Abstract

Polyhydroxyalkanoates (PHAs) have been established as biodegradable polymers since the second half of the twentieth century. Altering monomer composition of PHAs allows the development of polymers with favorable mechanical properties, biocompatibility and desirable degradation rates, under specific physiological conditions. Hence, the medical applications of PHAs have been explored extensively in recent years. PHAs have been used to develop devices, including sutures, nerve repair devices, repair patches, slings, cardiovascular patches, orthopedic pins, adhesion barriers, stents, guided tissue repair/regeneration devices, articular cartilage repair devices, nerve guides, tendon repair devices, bone-marrow scaffolds, tissue engineered cardiovascular devices and wound dressings. So far, various tests on animal models have shown polymers, from the PHA family, to be compatible with a range of tissues. Often, pyrogenic contaminants copurified with PHAs limit their pharmacological application rather than the monomeric composition of the PHAs and thus the purity of the PHA material is critical. This review summarizes the animal testing, tissue response, in vivo molecular stability and challenges of using PHAs for medical applications. In future, PHAs may become the materials of choice for various medical applications.

Keywords::

• animal testing
• in vivo tissue responses
• PHA medical devices
• polyhydroxyalkanoates
• tissue engineering

Acknowledgements

This work was supported by the Engineering and Physical Sciences Research Council, UK grant no. EP/C515617/1(P). Sabeel Valappil has also been provided financial support by the University of Westminster, London, UK. Superb Misra was supported by an Overseas Research Scholarship. We would like to thank V Misra and S Jagdish for reading and giving constructive comments on the manuscript. Aldo R Boccaccini and Ipsita Roy contributed eqaully to the composition of this review.

Notes

3HHX: 3-hydroxyhexanoate; 3HO: 3-hydroxyoctanoate; ICI: Imperial Chemical Industries; P(3HB): Poly(3-hydroxybutyric acid); P(3HB-co-3HV): Poly(3-hydroxybutanate-co-3-hydroxyvalerate; PHA: Polyhydroxyalkanoates.