Preparation and characterization of bioactive glass and hydroxyapatite containing polycaprolactone nanofibers by electrospinning method

Bioactive glasses are used in tissue engineering applications due to their binding ability to bone tissue by forming strong bonds with living tissue. In this study, polycaprolactone (PCL) fibrous composite scaffolds containing silica-based (13-93, 45S5) and borate-based (13-93B3) bioactive glass powders and fibers and hydroxyapatite (HA) were produced by electrospinning method. The silica-based 13-93 and 45S5 fibers used as additives in the project were prepared by electrospinning method. Structural and morphological properties of produced bare PCL, bioactive glass and HA containing PCL fibrous composites were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-Ray diffractometer (XRD), fourier transform infrared spectrophotometer (FTIR-ATR) and in vitro bioactivities were investigated by immersion in simulated body fluid (SBF) depending on time. The degredation behavior of the scaffolds was studied by immersing in phosphate buffer solution and ion release properties were analyzed by inductively coupled plasma emission spectrometer (ICP-OES). According to the results, fiber diameters of composite scaffolds produced were higher than bare PCL fibrous scaffolds. Water absorption capacities of PCL composite scaffolds containing 45S5 fiber and powder were measured to be above 100%. The porosity of the prepared samples was between 93% and 97%. According to the mass loss results of PCL composite scaffolds with and without additives in phosphate buffer solution (PBS) for 30 days, the contribution of bioactive glass powder and fibers increased the surface reactivity of the scaffolds and accelerated degredation behaviour. In addition, time-dependent increase in ion release behaviour was observed. It was concluded that the differences observed in the ion release may be due to the different surface reactivities of the additives with their dimensional and morphological properties. According to the results of atomic force microscopy analysis, compared to pure PCL scaffolds, the roughness of bioactive glass and HA containing scaffolds were higher. The addition of bioactive glass and HA to the PCL matrix increased the bioactivity of fibrous scaffolds. The high surface roughness of borate-based 13-93B3 bioactive glass containing scaffolds was attributed to the formation of HA layer by showing higher bioactivity in simulated body fluid. Fourier transform infrared spectroscopy analysis showed that the rate of HA formation of the 13-93B3 containing sample was higher. Additional, there is a direct correlation between FTIR analysis and scanning electron microscopy (SEM) micrographs, the residence time in SBF and their ability to form HA. The results of the study showed that bioactive glass and HA containing scaffolds have potential to be used in tissue engineering applications.