No abstract

In this study, a poly(e-caprolactone) (PCL)/bioactive glass (BG) nanocomposite was fabricated using BG nanofibers (BGNFs) and compared with an established composite fabricated using microscale BG particles. The BGNFs were generated using sol-gel precursors via the electrospinning process, chopped into short fibers and then incorporated into the PCL organic matrix by dissolving them in a tetrahydrofuran solvent. The biological and mechanical properties of the PCL/BGNF composites were evaluated and compared with those of PCL/BG powder (BGP). Because the PCL/BG composite containing 20 wt % BG showed the highest level of alkaline phosphatase (ALP) activity, all evaluations were performed at this concentration except for that of the ALP activity itself. In vitro cell tests using the MC3T3 cell line demonstrated the enhanced biocompatibility of the PCL/BGNF composite compared with the PCL/BGP composite. Furthermore, the PCL/BGNF composite showed a significantly higher level of bioactivity compared with the PCL/BGP composite. In addition, the results of the in vivo animal experiments using Sprague-Dawley albino rats revealed the good bone regeneration capability of the PCL/BGNF composite when implanted in a calvarial bone defect. In the result of the tensile test, the stiffness of the PCL/BG composite was further increased when the BGNFs were incorporated. These results indicate that the PCL/BGNF composite has greater bioactivity and mechanical stability when compared with the PCL/BG composite and great potential as a bone regenerative material. '

Calcium sulfate hemihydrate (CSH) powders were synthesized for use as bone cement by heat treating calcium sulfate dihydrate (CSD) powders in boiling CaCl 2 solutions with various CaCl 2 concentrations, ranging from 23.5 to 35.5 wt%, in order to control their morphology. All of the prepared CSH powders showed X-ray diffraction peaks corresponding to the CSH structure without any secondary phases, implying complete conversion from the CSD phase to the CSH phase. It was also observed that the concentration of CaCl 2 significantly affected the morphology of the CSH powder that was synthesized. In other words, as the CaCl 2 concentration was decreased from 35.5 to 23.5 wt%, the morphology notably changed from long-and-slim hexagonal rods with an aspect ratio of 5.5 to fat-and-short hexagonal columns with an aspect ratio of 1.4. This reduction in the aspect ratio led to a significant improvement in the compressive strength of the CSD cement prepared by mixing the CSH powders with water.