Fabrication of HA Nano-crystal Reinforced PHAs based composites for orthopedic fracture-fixing accessories using sustainable resources

The increasing demand for biodegradable polymers in orthopedic applications has significant potential to be used as temporary implants. In this regard, metallic implants are already being used in biomedical fields for permanent implants. These implants are non-biodegradable, and re-surgery is required for their removal after healing. Polyhydroxybutyrate (PHB) becomes the major focus of attention in biomedical implants because it is temporary and is resorbed by the tissues after healing. In the present study, bacterial isolate Bacillus endophyticus BE01HL001 was used to produce PHB using pentosan-rich sugarcane trash hydrolysate and evaluate their functional and biological properties. The chemical and structural composition of extracted PHB has also been determined. The extracted PHB shows high thermal stability at 267 °C using differential thermal analysis (DTA). The major limitation of PHB is its low osteoconductivity, which restricts its use in orthopedic applications. Therefore, an attempt has been taken to improve the bioactivity of PHB by reinforcing it with bioactive ceramic hydroxyapatite (HA). The degree of crystallinity of PHB/HA composites increases from 71 to 89% with an increase in HA (5% to 20%). Due to the agglomeration, the decrement in tensile strength was observed with an increment of nano-sized HA, and in vitro evaluation in simulated body fluid (SBF) for up to 28 days showed enhanced apatite layer formation and significant degradation resistance of the composite structure. In vitro cytotoxicity assay revealed high growth and proliferation of osteosarcoma cells on HA-reinforced PHB composite. These attributes of PHB/HA composites make it suitable for use in orthopedic fracture-fixing accessories.Please check the edit made in the article title.We have checked the edit made in the article title and approved the same. Graphical abstract