Tissue engineering scaffolds produced by electrospinning feature a structural similarity with the natural extracellular matrices. In this study, for the first time, poly(ε-caprolactone) (PCL)/hydroxyapatite (HA) and chitosan/poly(vinyl alcohol) (PVA) were simultaneously electrospun from two different syringes and mixed on a rotating drum to prepare homogeneous nanofibrous composite scaffold. The concentration of the spinning solutions and the ratios of PCL/HA-chitosan/PVA were varied and adjusted to acquire nanofibres with narrow diameter distribution. It was found that the PCL/HA spun fibres became thick and non-uniform in diameter by decreasing the solution concentration and voltage, and yet the effect of flow rate was negligible. Meanwhile, the diameters of chitosan/PVA fibres decreased and became more uniform by decreasing the solution concentration and tip-to-target distance. Furthermore, HA nanocrystals reinforce the scaffold and increase its mechanical strength, though by changing its mechanical behaviour make it more brittle. SEM morphology of the PCL/HA electrospun nanocomposite revealed that HA nanocrystals were kept suspended in solution during the electrospinning process, and laid inside the PCL nanofibres. This feature may provide a mechanism for controlled release of HA nanoparticles in cell culture studies. It was assumed that the nanofibrous composite scaffold of electrospun PCL/HA-chitosan/PVA can potentially be used for the osteogenic differentiation of stem cells.

In recent years, nanocomposite scaffolds made of bioactive polymers have found multiple applications in bone tissue engineering. In this study composite nanofibrous structure of gelatin (Gel)/chitosan (Cs)-polycaprolactone (PCL) containing hydroxyapatite (HA) were fabricated using co-electrospinning process. To assay the biocompatibility and bioactivity of electrospun nanocomposite scaffolds, the behavior of human osteosarcoma cells (MG63) on fabricated nanofibers was evaluated using scanning electron microscopy (SEM), fluorescence microscopy analysis, measuring calcium deposits and MTT assay. The SEM micrographs at days 3 and 7 showed high cell attachment and spreading on the nanofibrous scaffolds. The MTT results demonstrated the proliferation of MG-63 cells during 10 days and the positive effect of nanofibers in comparison of cell culture plate. Considering the proliferation rate and calcification extent, the Gel-Cs-HA nanofibers reveal highest biocompatibility for osteoblast cells which could be attributed to the smaller diameter fibers and more mechanical strength in the Gel-Cs-HA scaffold.

Natural biomaterials such as collagen, silk fibroin, and chitosan, and synthetic biopolymers such as polylactic acid, polycaprolactone, polyglycolic acid, and their copolymers are being used as scaffold for tissue engineering applications. In the present work, a fibrous mat was electrospun from eri silk fibroin (ESF). A composite of hydroxyapatite (Hap) and the ESF scaffold was prepared by soaking the ESF scaffold in a solution of calcium chloride and then in sodium diammonium phosphate. The average tensile stress of the pure ESF and hydroxyapatite-coated ESF scaffold (ESF-Hap) was found to be 1.84 and 0.378 MPa, respectively. Pure ESF and ESF-Hap scaffolds were evaluated for their characteristics by a themogravimetric analyzer and Fourier transform infrared spectroscope. The crystallinity and thermal stability of the ESF-Hap scaffold were found to be more than that of uncoated eri silk nanofiber scaffold. The water uptake of the pure ESF and ESF-Hap scaffolds was found to be 69% and 340%, respectively, in distilled water as well as phosphate buffer saline. The hemolysis percentage of both scaffolds was less than 5%, which indicate their good blood compatibility. The cytocompatibility studied by 3- (4, 5-dimethyl) thiazol-2-yl-2, 5-dimethyl tetrazolium bromide assay showed that the scaffold is biocompatible. To assess cell attachment and growth on the scaffold, human mesenchymal stem cells were cultured on the scaffolds.The results from scanning electron microscopy and fluorescent microscopy showed a notable cellular growth and favorable morphological features. Hence, the ESF-Hap scaffold is better suited for cell growth than the pure ESF scaffold.

Abstract. Hydroxyapatite (HA) scaffold is commonly used in the applications of bone tissue engineering due to its bioactivity and equivalent chemical composition to the inorganic constituents of human bone. The present study focused on the fabrication of porous 3D hydroxyapatite scaffold which was modified by polymer coating as a successful strategy to improve the mechanical properties. A 3D porous hydroxyapatite scaffolds were fabricated by gel-casting method by using freshly extracted egg yolk (EY) with (50 and 60)wt% of HA powder. To enhance the mechanical properties, composite PVA/ HA scaffolds were produced by using dip coating in Polyvinyl alcohol (PVA). Fourier transform infrared spectroscopy (FTIR) was used to recognize the functional group associated with the hydroxyapatite scaffolds before and after PVA coating. The physical (density and porosity) and mechanical (compressive strength and elastic modulus) properties were investigated before and after coating. SEM was used to inspect the surface morphology and pore modification of the scaffolds. Wettability was determined by using a water contact angle to analyze the scaffold hydrophobicity. Surface roughness was studied by atomic force microscopy (AFM). It was revealed that the scaffold porosity decreased with increase solid loading of HA powder in the gel and after PVA coating. The findings showed that PVA coating improved mechanical strength of scaffold to be double by covering the small pores and filling microcracks sited on the scaffold strut surfaces, inducing a crack bridging mechanism. The scaffolds’ strength was in the range of trabecular bone strength. This indicates  non-load bearing applications.