Shish-Kebab Nanohydroxyapatite-TiO₂ Nanofiber: A Biomimetic Platform for Regenerative Medicine

Abstract

Flexible titanium dioxide (TiO₂) nanofibers are gaining considerable attention in bone tissue engineering owing to their superior biocompatibility, extensive surface area, and structural adaptability. This study explores the synthesis of flexible TiO₂ nanofibers and its in vitro evaluation for biomineralization capability. The Flexible TiO₂ NFM was fabricated employing electrospinning technique followed by controlled calcination. The SEM-EDS, TEM, XRD, and FTIR analysis were done to characterize and to confirm the biomineralization of the flexible TiO₂ NFM.  Surface analysis via scanning electron microscopy (SEM) revealed the progressive formation of apatite-like layers. Elemental confirmation was provided by energy-dispersive X-ray spectroscopy (EDS), which identified the presence of calcium (Ca) and phosphorus (P), with Ca/P ratios nearing the ideal value for stoichiometric hydroxyapatite (~1.64). EDS spectra displayed characteristic peaks for oxygen at~0.52 keV, calcium at 3.69 keV & 4.01 keV, and phosphate 2.01 keV, confirming the deposition of calcium phosphate and the effectiveness of the biomineralization process. XRD analysis for biomineralized NFM showed distinct peaks at 2θ values of 28.5°, 31.7°, and 66.3°. Likewise FTIR analysis showed notable alterations with characteristics peaks at 3418 cm⁻¹ suggesting increased hydrophilicity, and 1625.96 cm⁻¹, 1394.55 cm⁻¹, 1034.65 cm⁻¹ for confirmation of calcium phosphate phase, such as hydroxyapatite. The presence of granular textures on the fiber surface indicated the successful formation of apatite-like structures. TEM analysis revealed a well-defined crystalline core surrounded by a biomineralized layer, closely resembling the mineral composition of natural bone. The results of XRD and FTIR peaks further confirmed the biomineralization of flexible TiO₂ NFM.