Superparamagnetic iron oxide-hydroxyapatite composite coatings for bio-imaging, hyperthermia and orthopedic applications

Hydroxyapatite (HA) is a remarkable biomaterial utilized for various biomedical applications. The incorporation of iron oxide (Fe 3 O 4 ) nanoparticles into HA provides a versatile platform for the development of highly efficient nanocomposites, owing to the exceptional properties of Fe 3 O 4 , ideal for tissue engineering, bioimaging and hyperthermia applications. The current study focusses on the development of Fe 3 O 4 -HA composites with different concentrations of Fe 3 O 4 (2.5, 5 and 7.5 %). The characterization of the composites was performed using XRD, FT-IR, SEM and VSM analyses. The anti-bacterial activity of the composites was determined against a gram-positive and gram-negative bacteria. The heating capacity of the composites was analyzed to determine its hyperthermia potential. The efficiency of the composites as an MRI contrast agent was also examined. It was observed that 5 % Fe 3 O 4 -HA was hemocompatible and also exhibited good efficacy as a hyperthermia and T 2 weighted MRI contrast agent. Therefore, 5 % Fe 3 O 4 -HA coatings were produced on Ti–6Al–4V to improve the functional behavior of the bone implants. The bioactivity studies showed that the coatings have the ability to form bone-like apatite layer on the surface of the implant. The coatings also revealed good mechanical properties as displayed through Vickers microhardness. The in-vitro cytotoxicity study on L929 fibroblast cells indicated the enhancement of the proliferation of cells on the surface, making it suitable for bone regeneration applications. These results confirmed that the synthesized composites can act as a potential candidate for bioimaging, magnetic hyperthermia and tissue engineering applications. • Sol-gel synthesis of HA-Fe 3 O 4 composites with different concentration of Fe 3 O 4 . • Superparamagnetic nature of the composites confirmed its potential as T2 MRI contrast agents and for hyperthermia. • 5 wt% of Fe 3 O 4 -HA was chosen for spin coating on Ti–6Al–4V at different RPM owing to its superior hemocompatible nature. • Coatings developed at 4000 RPM were uniform and compact and showed better mechanical strength. • The biocompatible nature of the coatings was ensured using MTT assay with L929 fibroblast cell lines.