Polyhydroxyalkanoates and their advances for biomedical applications

Polyhydroxyalkanoates (PHAs) are sustainable, versatile, biocompatible, and bioresorbable polymers that are suitable for biomedical applications. Produced via bacterial fermentation under nutrient-limiting conditions, they are uncovering a new horizon for devices in biomedical applications. A wide range of cell types including bone, cartilage, nerve, cardiac, and pancreatic cells, readily attach grow and are functional on PHAs. The tuneable physical properties and resorption rates of PHAs provide a toolbox for biomedical engineers in developing devices for hard and soft tissue engineering applications and drug delivery. The versatility of PHAs and the vast range of different PHA-based prototypes are discussed. Current in vitro, ex vivo, and in vivo development work are described and their regulatory approvals are reviewed. Polyhydroxyalkanoates (PHAs) are polymers produced sustainably via bacterial fermentation under nutrient-limiting conditions.Both the degradation profile and the mechanical properties of PHAs can be tuned.PHA-based scaffolds have demonstrated excellent biocompatibility with a wide range of cell types including but not limited to bone, cartilage, nerve, cardiac, and pancreas, and have exhibited no notable cytotoxicity or inflammatory and immune responses in vivo.The FDA has approved poly(4-hydroxybutyrate) for use in biomedical applications, and this is already widely used in sutures and hernia meshes in the clinic.Recent advances in processing have shown that PHAs have high potential for use as the base material in a large variety of biomedical prototypes including wound-healing patches, cardiac patches, heart valves, bone scaffolds, cartilage scaffolds, and nerve guidance conduits.