Microbial polyhydroxyalkanoates as medical implant biomaterials.

Polyhydroxyalkanoates (PHAs), a diverse biopolyester synthesized by many bacteria as intracellular carbon and energy storage materials, have been produced in large quantity for various application researches including medical implants for approximately 30 years. It has been demonstrated by many studies that PHAs possess the required mechanical, biodegradable and tissue-compatible properties for implant applications. Very importantly, common PHA biodegradation products including oligomers and monomers are also not toxic to the cells and tissues. Some PHA degradation products have been studied for pharmaceutical applications. Mechanisms of PHA that stimulate cell growth were revealed. So far, no study has been reported to have any carcinogenesis result induced by any PHA or their biodegradation products. All results point to the feasibility of PHA to be developed into various bio-implant products.