One-pot hydrothermal synthesis of a magnetic hydroxyapatite nanocomposite for MR imaging and pH-Sensitive drug delivery applications

Synthetic hydroxyapatite (HA) due to its high biocompatibility, anti-inflammatory properties, high stability, and a flexible structure in combination with magnetic nanoparticles has the strong potential to be used in modern medicine including tissue engineering, imaging, and drug delivery. Herein, a hydrothermal process was used to prepare magnetite nanoparticles dispersed on the hydroxyapatite nanorods with cetyltrimethylammonium bromide (CTAB) as a surfactant. Characterization study of the synthesized iron oxide-hydroxyapatite (IO-HA) nanocomposite was performed by FT-IR spectroscopy, X-ray powder diffraction, energy dispersive X-Ray analysis (EDX) for elemental mapping, transmission electron microscopy, and vibrating sample magnetometer. Then, the biocompatibility of the synthesized nanocomposite studied by 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay and hemocompatibility assay. Focus on this point, curcumin loaded IO-HA (Cur@IO-HA) was developed for exploring the pH-sensitivity of the drug carrier and then evaluating its cellular uptake. The in vitro efficacy of the synthesized nanocomposites as a magnetic resonance imaging (MRI) contrast agent was also investigated. Our results showed that IO-HA nanocomposite is non-cytotoxic and hemocompatible as well as a good pH-sensitive drug carrier and a favorable MRI T2 contrast agent. Comparing to the free curcumin, Cur@IO-HA displayed a good cellular uptake. Taking into account the above issues, IO-HA nanocomposite has the most potential for application as a theranostic MRI contrast agent.