Ultrasound-assisted fabrication of a biocompatible magnetic hydroxyapatite

Hydroxyapatite with magnetic core: Synthesis methods, properties, adsorption and medical applications

This review presents the actual state of knowledge and recent research results on the magnetic composite synthesized from iron oxide (γ-Fe₂O₃ or Fe₃O₄) and hydroxyapatite. It can be obtained applying some methods, i.e. chemical precipitation, hydrothermal, sol-gel, and biomimetic or combined techniques which exhibit characteristic properties affecting the form of the prepared product. More specific details are discussed in this paper. A comparison of the discussed synthesis methods is presented. On the basis of selected publications, a comparison of the results of the analysis by XRD, FTIR, SEM and EDX methods for hydroxyapatite with a magnetic core was also presented. Moreover, the characteristics large adsorption capacity and specific area allow employing nanocomposites as adsorbents particularly in removal of toxic metal ions. Nowadays this issue is extremely vital due to large amounts of pollutants in the environment and greater ecological awareness of people. Moreover, magnetic hydroxyapatite can be also applied as a catalyst in various syntheses or oxidation reactions as well as in medicine in magnetic resonance imaging, hyperthermia treatment, drug delivery and release, bone regeneration or cell therapy.

Biocompatible HA@Fe3 O4 @N-CDs hybrids for detecting and absorbing lead ion

The trinary hydroxyapatite@Fe₃ O₄ @N-doped carbon dots (HA@Fe₃ O₄ @N-CDs) hybrids were prepared by one-pot hydrothermal approach and utilized to detect and remove lead ion from aqueous solution. The structures and morphologies of as-obtained nanorod-like HA@Fe₃ O₄ @N-CDs hybrids were characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy measurements. These HA@Fe₃ O₄ @N-CDs hybrids possess good magnetism by magnetic hysteresis test and multi-colored fluorescence by the CLSM measurement. Furthermore, the as-obtained hybrids display excellent biocompatibility by MTT assay. Importantly, the trinary magnetic HA@Fe₃ O₄ @N-CDs hybrids as a green detector and adsorbent of Pb²⁺ were investigated. The influence of the different pH, the concentration of heavy metal, and the maximum adsorption capacity on removal efficiency was measured in detail. The maximum Pb²⁺ adsorption capacity on HA@Fe₃ O₄ @N-CDs hybrids is 450 mg/g. The kinetic mechanism was a pseudo-second order model, and the isotherm data was fitted well by the Langmuir isotherm and Freundlich model. Hence, the nanorod-like HA@Fe₃ O₄ @N-CDs hybrids could be a multifunctional material with significant potential applications in heavy metal detection and adsorption, bone tissue regeneration, magnetic therapy, and biomedicine. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2019.

Structural features of hydroxyapatite and carbonated apatite formed under the influence of ultrasound and microwave radiation and their effect on the bioactivity of the nanomaterials

The samples of hydroxyapatite and carbonate substituted hydroxyapatite (CHA) were obtained under the influence of physical factors, namely ultrasound (US) and microwave (MW) radiations. The results of Fourier transform infrared spectroscopy and X-ray diffraction analysis have proved the formation of the calcium deficient hydroxyapatite and B-type CHA with the Ca/P ratio in the ranges 1.62-1.87. In vitro studies have showed the increased bioactivity of the samples, synthesized under the influence of physical factors as compared to the standard ones. The samples of both groups, synthesized under the influence of 600 W MW, have shown the greatest stability in biological environment. In vivo tests confirm that obtained under US and MW radiations hydroxyapatite-based biomaterials are biocompatible, non-toxic and exhibit osteoconductive properties. The usage of US and MW radiations can significantly shorten the time (up to 5-20 min) of obtaining of calcium deficient hydroxyapatite and B-type CHA in nanopowder form, close in structure and composition to the biological hydroxyapatite.

Calcium-based biomaterials for diagnosis, treatment, and theranostics

Calcium-based biomaterials with good biosafety and bio-absorbability are promising for biomedical applications such as diagnosis, treatment, and theranostics.