Oxidative Precipitation Synthesis of Calcium-Doped Manganese Ferrite Nanoparticles for Magnetic Hyperthermia

Superparamagnetic nanoparticles are of high interest for therapeutic applications. In this
work, nanoparticles of calcium-doped manganese ferrites (CaxMn1􀀀xFe2O4) functionalized with
citrate were synthesized through thermally assisted oxidative precipitation in aqueous media. The
method provided well dispersed aqueous suspensions of nanoparticles through a one-pot synthesis,
in which the temperature and Ca/Mn ratio were found to influence the particles microstructure
and morphology. Consequently, changes were obtained in the optical and magnetic properties that
were studied through UV-Vis absorption and SQUID, respectively. XRD and Raman spectroscopy
studies were carried out to assess the microstructural changes associated with stoichiometry of the
particles, and the stability in physiological pH was studied through DLS. The nanoparticles displayed
high values of magnetization and heating efficiency for several alternating magnetic field conditions,
compatible with biological applications. Hereby, the employed method provides a promising strategy
for the development of particles with adequate properties for magnetic hyperthermia applications,
such as drug delivery and cancer therapy.