Fabrication and characterization of Ag doped hydroxyapatite-polyvinyl alcohol composite nanofibers and its in vitro biological evaluations for bone tissue engineering applications

Electrospinning is one of the promising techniques to fabricate the nanofiber based scaffold for bone regeneration applications. In this study, firstly sol-gel method was employed to synthesize 5 % of Ag doped hydroxyapatite and also 10 wt% of polyvinyl alcohol solution was prepared for the electrospun process. For the first time, we have successfully fabricated the composite nanofibers in the combination of various concentration of Ag doped hydroxyapatite such as 1, 2, 3, and 5 wt% with polyvinyl alcohol solution. The developed Ag doped hydroxyapatite-polyvinyl alcohol composites were further characterized by Fourier transform infrared spectroscopy and powder-X-ray diffraction analysis to examine the characteristic functional groups and phase composition of Ag doped hydroxyapatite embedded into polyvinyl alcohol matrix. The uniform distribution of Ag doped hydroxyapatite in polyvinyl alcohol polymer with nanofiber diameter of 188-242 nm range was confirmed by high resolution transmission electron microscope and dynamic light scattering analysis, also the chemical/elemental composition was observed by scanning electron microscopy-energy dispersive spectroscopy analysis. The antibacterial activity was evaluated for the fabricated Ag doped hydroxyapatite polyvinyl alcohol composite nanofibers by using Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) pathogens and the results demonstrated that E. coli exhibits excellent zone of inhibition than S. aureus due to its lesser cell wall thickness. The hemocompatibility study proves that the developed composite nanofibers are blood compatible and showed the hemolytic ratio of less than 5 %. In addition to this, in vitro bioactivity assessment was carried out for 7 days by immersing in simulated body fluid solution to generate the dense apatite layer on their surfaces which was further examined by X-ray diffraction and scanning electron microscopy-energy dispersive spectroscopy analysis. Hence, these electrospun fabricated Ag doped hydroxyapatite-polyvinyl alcohol composite nanofibers will acts as a potential scaffold material for tissue engineering applications.