On the possible applications of magnetic ionic liquids in magnetic hyperthermia

The rapid increase in ionic liquid (IL) studies generates several possibilities for applying these ‘green’ compounds in biomedicine. This inspired us to explore the potential application of magnetic ILs (MILs) in magnetic hyperthermia (MHT). This paper presents the results of the heating efficiency (HE) measurements for iron-based MILs. We examined two MILs, namely 1-butyl-3-methylimidazolium tetrachloroferrate (BmimFeCl 4 ) and 1-ethyl-3-methylimidazolium tetrachloroferrate (EmimFeCl 4 ), along with their anion precursor compounds (e.g. FeCl 3 ) in aqueous solutions. Heating experiments were conducted at a frequency of 356 kHz with magnetic field strengths up to 16.2 kA/m. The influence of different metals (Fe, Dy, Ho) in anion precursor compounds on HE was observed. Furthermore, we investigated the effects of metal concentration, the impact of their ligands, and the influence of the alkyl chain length of the cation on HE. The results provide data on the commonly used specific absorption rate (SAR) for the MILs and the selected solutions studied. Additionally, a new magnetothermal figure of merit (FoM) is introduced as guidance for designing MILs with potential applications in MHT opening this field for further exploration. • Magnetic ionic liquids heating efficiency was described by specific absorption rate. • Heating efficiency depends on metal content in ionic liquids and precursor compounds. • Effect of metals and ligands in precursor salts on heating efficiency was shown. • Heating efficiency dependence on magnetic field obeyed square field strength law. • Figure of merit from magnetic susceptibility and heat capacity was introduced.