Bio-inspired synthesis of bio-hydroxyapatite/synthetic hydroxyapatite hybrid nanosystems

The current study focuses on the synthesizing of novel hybrid nanosystems of bio-hydroxyapatite (BioHAp)/synthetic-hydroxyapatite (HAp-Syn). Bio-HAp was defatted, deproteinized, and then sonicated to obtain nanoparticles (nBioHAp). Hybrid nanosystems (HNS) were synthesized by wet chemical precipitation using nBioHAp as nucleation sites and applying four different precipitation times of 45, 90, 135, and 180 min. X-ray diffraction (XRD) showed that the patterns of the nBioHAp and HAp-Syn samples have broadened diffraction peaks due to simultaneous elastic and inelastic scattering. Their crystallite size is about 25 nm, while the hybrid nanosystems have a size between 35 and 40 nm. Fourier-transform infrared spectroscopy (FT-IR) revealed the main groups associated with hydroxyapatite (PO₃²⁻, OH⁻, and CO₃²⁻), and the nanometer character of the crystals was demonstrated by studying the full width at half maximum (FWHM) of the spectra. Scanning electron microscopy (SEM) revealed the differences between the morphologies of nBioHAp and HAp-Syn. The shape of HNS resembled that of biogenic HAp, which was confirmed by transmission electron microscopy (TEM). Inductively coupled plasma spectroscopy (ICP-OES) and energy dispersive X-ray spectroscopy (EDS) were used to confirm the elemental composition of Mg, Na, K, and Zn as minority ions.