Fabrication and Characterization of Electrospun Polycaprolactone/Gelatin and Bioactive Glass Bilayer Nano-fibrous Scaffold for Bone Tissue Engineering

Abstract

Bone tissue engineering has been recently introduced by means of a scaffold material which promotes cellular adhesion, proliferation and differentiation, leading to new bone tissue formation. Amongst the methods used for scaffold fabrication is electrospinning, which produces nanofibers that mimic the extracellular matrix, allowing for better cellular response. Blending a synthetic polymer with a natural polymer and a bioactive material could provide a biodegradable scaffold with suitable mechanical, physical and biological properties. The aim of this study was to fabricate and characterize the properties of nanofibrous scaffolds used for bone tissue engineering by preparing a bilayer scaffold composed of a nanofibrous layer of polycaprolactone (PCL) and gelatin (Gt) as the base layer, followed by direct deposition of a nanofibrous layer of bioactive glass (BG) using electropsinning as the method of fabrication. The properties were assessed in comparison to scaffolds fabricated using different blends of these biomaterials (PCL, PCL/Gt, PCL/Gt/BG and PCL&PCL/BG bilayer). A total of 328 scaffolds were prepared from five different groups. The scaffolds were characterized by measuring their mean fiber diameter using scanning electron microscopy coupled with Image J analysis software. Transmission electron microscopy was used to confirm the incorporation of BG nanoparticles within the nanofibers. The functional chemical groups were assessed using Fourier transform infrared spectroscopy. Surface area and porosity were measured using the nitrogen adsorption method as well as mercury intrusion porosimetry. Moreover, in-vitro bioactivity, swelling ratio and weight loss percentages were evaluated by immersing the scaffolds in simulated body fluid (SBF) for up to 14 days. In- vitro bioactivity was assessed using SEM analysis of the scaffolds' surface morphologies accompanied by elemental analysis using energy dispersion X-ray (EDX) spectroscopy. Swelling and weight loss percentages were measured by calculating the samples' weights before and after immersion in SBF. Furthermore, the tensile strengths and elastic moduli were measured to assess their mechanical properties. Finally, MTT assay was used to test the cytotoxicity of the PCL/Gt&PCL/BG nanofibrous bilayer scaffold.