Synthesis and characterization of nano-hydroxyapatite rods/poly(l-lactide acid) composite scaffolds for bone tissue engineering

The aims of this work were synthesis of rod shaped nano-hydroxyapatite (nHAP) and fabrication of novel nano-hydroxyapatite/poly(l-lactide acid) (nHAP/PLLA) composite scaffold. In the first step, the identification and morphology of chemically synthesized nHAP particles were determined by XRD, EDX, FTIR and SEM analyses. The rod shaped nHAP particles with an average size of approximately 37–65 nm in width and 100–400 nm in length were found similar to natural bone apatite in terms of chemical composition and structural morphology. In the second step, nHAP and micro sized HAP (mHAP) particles were used to fabricate HAP filled PLLA (HAP/PLLA) composites scaffolds using thermally induced phase separation method. The porosity of scaffolds was up to 85.06% and their average macropore diameter was in the range of 64–175 μm. FTIR and XRD analyses showed some molecular interactions and chemical linkages between HAP particles and PLLA matrix. The compressive strength of nanocomposite scaffolds could high up to 14.9 MPa while those of pure PLLA and microcomposite scaffolds were 1.79 and 13.68 MPa, respectively. The cell affinity and biocompatibility of the nanocomposite scaffold were found to be higher than those of pure PLLA and microcomposite scaffolds. Following the results, the newly developed nHAP/PLLA composite scaffold is comparable with cancellous bone in terms of microstructure and mechanical strength, so it may be considered for bone tissue engineering applications.