Abstract: | In this paper, we considered the optimization of the magnetic-resonance imaging properties of nanosystems that are based on ultrasmall nanoparticles of complex iron oxide by modifying their chemical composition with Zn, Mn, Mg, or Co. The relationship between the chemical composition, crystal structure, magnetic phase, and contrast-imaging properties of the nanoparticles was investigated. The comparative cytotoxicity of the nanoparticle solutions on HeLa cells was studied. The prospects for these types of nanosystems for the development of contrast MRI agents with the predominant effect on the T1 or T2 parameters of the body tissues were shown. |