A multilayer biomimetic chitosan-gelatin-fluorohydroxyapatite cartilage scaffold using for regenerative medicine application

In the present study, pure chitosan and gelatin solutions are blended at four various ratios with the addition of Fluorohydroxyapatite (FHA). The specimens are fed into the Freeze-Drying (FD) apparatus to produce porous architectures. The X-ray Diffraction (XRD) and the Scanning Electron Microscopy (SEM) are used for analyzing the solutions and finding the best solution regarding the number of beads and droplets, yielded fibers, and morphological uniformity. The flow rate, voltage, and distance from the needle to the collector are variate in the selected specimen for examining the impact processing parameters on fibers morphology and nanofibers diameter. The in-vitro biocompatibility examination is executed with human skin fibroblasts to distinguish the cell proliferation level on the scaffolds. The results obtained by XRD and SEM confirmed that the specimen containing 70% and 30% chitosan and gelatin, respectively, includes the minimum number of beads, droplets, yielded fibers, and the maximum morphological uniformity. Then, the in-vitro biocompatibility tests confirmed high and acceptable biological properties for the specimen. For more details, the experimental tests report that S1 has the maximum displacement value of 207.64 nm, while S4 represents the lowest displacement value of 175.87 nm. Moreover, the numerical study indicated that the scaffold compressive strength increases from 22.8 MPa (S1) to 31.2 MPa (S4) with the addition of 30 wt % FHA nanoparticles. Nanoindentation finite element simulation proved that the indenter penetration decreases from 215.54 nm to 181.46 nm with the addition of 30 wt % FHA nanoparticle. As a consequence, Chitosan-gelatin/FHA/30 wt % FHA (S4), has the best mechanical properties.