Fabrication of polymer-bioactive glass nanocomposite materials in bone tissue engineering applications

The main driving idea of the study was to produce nano-scaled bioactive glass/polymer composite scaffolds with the inclusion of relevant ions in order to develop multifunctional scaffolds for bone tissue engineering. The originality of the study was related to the integration of several functions in a single advanced scaffold composite system based on specific compositions of bioactive glasses, providing a platform for the delivery of therapeutic ions, and biodegradable polymers as the backbone material. This new material was aimed to have the capacity, through engineered nanoparticles and tailored kinetic release of specific ions, to stimulate early angiogenesis and provide an ideal scaffold for cell recruitment and proliferation, thereby accelerating the bone repair process. In this context, nano-scaled materials from polymer blends (e.g., gelatin/sodium alginate and gelatin/poly(ε-caprolactone)), as well as their composites with bioactive glasses were fabricated with the use of electrospinning technique. In electrospinning technique, solutions containing blends of polymers without or with bioactive glass particles were prepared to be converted into electrospun nanofibers at the relevant conditions. For this purpose, the optimal solution parameters (i.e., concentration of each polymer solution, ratio of one polymer to another, and solvent composition) to produce polymeric scaffolds were first investigated by using Box-Behnken design technique. Secondly, the processing parameters (e.g., applied voltage, tip-to-collector distance, and feeding rate) were also optimized in order to conduct a stable electrospinning process and to have a desirable surface topography.Then, cross-linking treatment was also carried out for enhancing the surface properties of the obtained scaffolds. After that, microstructural and physical properties of the polymeric and nanocomposite scaffolds were determined by using scanning electron microscope, X-ray diffraction, Fourier transform infrared spectrophotometer, and differential thermal analyzer. Finally, a comprehensive in vitro simulated body fluid study was also evaluated to determine the bioactivity of the nanocomposite scaffolds. Furthermore, the release of therapeutic ions from the nanocomposite scaffolds was investigated by using inductively coupled plasma optical emission spectrometry. The overall results put forth that scaffolds obtained in this study could be promising candidates for bone tissue engineering applications.