Evaluation of magnetic heating capacity of unimagnetic and bimagnetic nanoparticles ligated with oleic acid and zwitterionic dopamine sulfonate dispersant for localized hyperthermia applications

Nanocolloidal magnetic nanoparticles (MNPs) are widely researched for many biomedical applications. Among them, localized magnetic hyperthermia application for cancer treatment is widely explored. It is obtained by superparamagnetic heating (SPH) through magnetic relaxation losses (MRL) under biocompatible alternate magnetic field (AMF). However, SPH capacity of nanoparticles is strongly depends on: mass magnetization, magnetic susceptibility, magnetic dipolar interactions, relaxation time, type of dispersant. Here both magnetic parameter, and dispersant type of MNPs were modified and studied their effect on SPH of both unimagnetic and bimagnetic core-shell nanoparticles (CSNPs). Magnetic parameters are modified through magnetic exchange bias field in bimagnetic CoFe2O4-MgFe2O4 and MgFe2O4-CoFe2O4 CSNPs, and magnetic anisotropy and cation distribution in unimagnetic CoFe2O4 and MgFe2O4 nanoparticles. Both the long chain oleic acid (OA) and short chain zwitterionic dopamine sulfonate (ZDS) dispersants were used for the study. Among the 24 samples studied, the ZDS ligated CoFe2O4-MgFe2O4 CSNPs shown high specific superparamagnetic heat power emission (SPE) of 899 Wg- 1 at 0.5 mg mL- 1 under 35.22 kA m-1 and 316 kHz AMF. ZDS ligated MgFe2O4-CoFe2O4 show 439 Wg- 1 at same concentration and field. Both the CSNPs ligated with ZDS dispersant have shown 100% cytocompatibility with human embryonic kidney 293 cells in MTT assay in 100-900 mu g mL- 1 range. The data were analyzed by MRL dependent heat emission by both Ne<acute accent>el and Brown relaxations.