Duality of iron (III) doped nano hydroxyapatite in triple negative breast cancer monitoring and as a drug-free therapeutic agent

All types of cancer, due to their high mortality rates, need new methods to obtain more accurate diagnosis and more efficient treatments. In response to this need, theranostic systems have emerged as simpler and more compact agents for cancer control, comprising a synergistic effect between both diagnostic and therapeutic features into one singular system. However, such simplicity depends on the type of materials and their physicochemical characteristics. In the present work, magnetic hydroxyapatite nanoparticles were produced by chemically doping hydroxyapatite nanoparticles with 10% iron (III) ions. This material was characterized in terms of its physicochemical properties, with emphasis on its magnetic features, and biological response in terms of in vitro toxicity evaluation, using human triple negative breast cancer cell lines, and comparing the results with those produced with non-doped hydroxyapatite nanoparticles. The obtained nanoparticles had a round shape and the chemical structure of hydroxyapatite. As expected, iron ions inclusion did not influence the general chemical composition of hydroxyapatite, neither its common hexagonal crystalline structure. However, it provided the material with a superparamagnetic behaviour and a saturation magnetization of 0.5 emu/g. Additionally, these nanoparticles created high contrast effects on magnetic resonance imaging, being adequate contrast agents for cancer diagnosis. Moreover, in terms of therapy, these nanoparticles proved to be toxic to cancer cells, inducing damage on both mitochondria and cell membrane, due to calcium and iron ions release, indicating that iron plays a major role in the overall dual functionality of these nanoparticles. Such findings are a novelty since this dual functionally, in this material, was never reported, serving as a foundation for further studies in order to create a full product for cancer theranostics.