Hydrothermal synthesis of hydroxyapatite nanorods and their use in PCL bone scaffold

It is urgently needed to synthesize hydroxyapatite (HAP) nanorods with controllable size to mimic the morphology and size of natural human bone mineral for bone regeneration. In this study, HAP nanorods with size closed to natural human bone mineral were synthesized via hydrothermal method by changing hydrothermal temperature. Then they were introduced into biopolymer polycaprolactone (PCL) scaffold fabricated by selective laser sintering (SLS) to enhance its properties. The results revealed that the lower hydrothermal temperature was more favorable for HAP crystals to grow along c-axis at the length direction, while the increase in temperature was more favorable for the crystal to grow along a-axis at the width direction. The well-crystallized HAP nanorods obtained by hydrothermal method at 160 °C for 8 h had a diameter of 30 nm and a length of 200 nm. The introduction of 10 wt% HAP nanorods into PCL scaffold enhanced the tensile strength and compressive strength by 98.38% and 127.60% than the PCL scaffold. Meanwhile, the PCL/10%HAP scaffold could induce the deposition of apatites with a Ca/P ratio of 1.67 on its surface, which implied that the scaffold possessed excellent bioactivity. Besides, the scaffold exhibited good biocompatibility for cell attachment, spreading and proliferation.