Magnetic nanocomposites for future theranostic medicine: Diagnostics (MRI and MPI) and Magneto-HyperThermic Treatment (MHT)

Magnetic nanocomposites (MNC) are currently being widely studied as materials for future medicine, such as for enhancing the contrast of magnetic resonance imaging, delivering drugs directly to the diseased organ, and for hyperthermia therapy of oncological diseases. MNC for biomedicine have core/shell (C/S) structure in which the core is magnetic nanoparticle with high magnetic characteristics but is often toxic. The shell covering the core is a biocompatible inorganic and/or organic layer (e.g., dextran, chitosan, silicon, etc.) which prevent aggregation and improve physicochemical stability in various physiological environments. Appropriate surface functionalization of MNPs allows highly selective chemical interaction with biological systems.

Magnetite (Fe₃O4), due to their biocompatibility, biodegradability and low toxicity, are widely studied for biomedical applications such as imaging (diagnostics) (MRI), targeted drug delivery, magnetic hyperthermia (MHT) treatment including cancer. They are used in MRI for increasing contrast of pictures, but the negative contrast effects of iron oxide can lead to errors in diagnostic. These errors are eliminated in a new highly sensitive magnetic powder imaging (MPI) diagnostic method proposed in 2000. The insignificance of the magnetic background from the biological environment allows MNCs to be used as (markers/tracers) in these new MPI method.

In recent years, the researchers has been aimed at the synthesis of Fe₃O₄ nanoparticles doped with divalent ions (M²⁺ =Zn, Ni, Mn, Co, etc.). The magnetic properties of Fe₃O₄ can be controlled by doping with M²⁺. The synthesis technology determines of the cation distribution in sublattices, particle size and shape, which are important parameters of MNCs. In addition, specially prepared water-dispersible MNCs are required for biomedicine.

The paper presents new multifunctional MNCs M_xFe_3-xO₄,  where M is divalent metal (Ni, Zn or Mg) and then functionalized with various acids. MNC were prepared by a two-step mode. In the first step, (Ni, Zn or Mg)_xFe_3-xO₄ MNPs were obtained by the hydrothermal method. In the second step, the synthesized MNPs were functionalized with polyacrylic, citric or oleic acids using coprecipitation method. Appropriate surface functionalization of MNPs allows highly selective chemical interaction with biological systems.

Comprehensive studies of the properties of the obtained nanocomposites and the effect of particle modification or functionalization with acids were carried out using X-ray, magnetic and Mössbauer measurements. Mossbauer Spectroscopy allows one to reliably establish the phase composition, distribution of iron ions over nonequivalent positions of the crystal lattice and their number, which is inaccessible to other methods.

Created biocompatible (Ni, Zn or Mg)_xFe_3-xO₄ MNCs meet the requirements for composites for theranostic treatment: MRI diagnostics, drug delivery and magnetic hyperthermia treatment. The characteristics of created NiFe₂O₄ MNP and functionalized by citric acid  MNC fully satisfy the requirements of the new biomedical method of visualization developed in 2000, which named of magnetic powder imaging (MPI) and is crucial for the transition from the experimental stage of MNC use to clinical practice. The insignificance of the magnetic background from the biological environment allows MNCs to be used as highly sensitive visualizers (markers/tracers) in MPI. 

Since 1969 A. Kamzin researches has involved to studying of the fundamental phenomena in magnetic materials. From 1990 his research programs are focused on the studding on the Biomedical applications of Magnetic and Ferroelecrtric Nanoparticles and Nanocomposites and creating new high effective composites for different applications: for biomedicine as well as for  water purification. He created new Magnetic Nanocomposites for MRI and MPI diagnostics, targeted drag delivery and Magnetic Hyperthermia Treatment of Cancer. He also created Magnetic Nanocomposites for Theranostic treatment: diagnostic + treatment. Research and Teaching Experience: 55 years. Academic Qualifications : M.Sc.(Phys.)-1970; Ph. D.-1978; Dr. of Science, Prof., Chief Researcher- 1994.