Multifunctional magnetic nanomaterials

A technique is being developed for obtaining stable homomeric and heteromeric magnetic chains from iron oxide nanoparticles, as well as cobalt ferrite, by their mutual covalent binding in a magnetic field. Their surface will be modified with a PEG polymer via nitrodophamine. Further, the end groups of PEG of one type of modified MNPs will be covalently modified with low molecular weight disulfide, after which a low molecular weight conjugate of nitrodophamine with maleimide will additionally be grafted to the surface of another type of MNPs also coated with PEG through nitrodophamine. Thus, on the surface of one type of MNCH there will be disulfide groups that can be reduced to thiols in a controlled manner, and maleimide groups will be located inside the polymer shell of other MNCH. Thiols will penetrate through the polymer shell and form covalent bonds with maleimides, but at the same time MNPs with identical chemical properties of the surface will not bind to each other – thus it will be possible to obtain heteromeric chains and at the same time not to obtain uncontrolled cross-linking of MNPs. Without a magnetic field, mutual shielding between MNCs will be observed. Periodic application of a magnetic field with interruptions will lead to the assembly of MNCs into chains, where their size can be controlled by the exposure time in the field. Further, the magnetic properties, namely hyperthermia, relaxivity and magnetomechanical activation of the obtained chains will be investigated and compared with the original MNCs. When obtaining nanocains with alternating soft magnetic and hard magnetic phases, MNF can lead to an exchange interaction between them, which will significantly increase the effectiveness of magnetic hyperthermia.