Comprehensive in-vitro and magnetic hyperthermia investigation of biocompatible non-stoichiometric Zn0.5Ca0.5Fe2O4 and Mg0.5Ca0.5Fe2O4 nanoferrites on lung cancer cell lines

In this research, the suitability and potential of two biocompatible mixed valent non-stoichiometric spinel nanoferrites viz., Zn0.5Ca0.5Fe2O4 (ZCNF) and Mg0.5Ca0.5Fe2O4 (MCNF) with a minor impurity of CaCO3 have been explored for magnetic hyperthermia and in-vitro cytotoxicity against normal and lung cancer cell lines. Nanocrystalline samples of ZCNF and MCNF in fcc structure were synthesized using the citrate-based sol-gel method and characterized by a variety of standard techniques. 57Fe Mössbauer spectroscopy, electron spin resonance and dc-magnetometry studies revealed that ZCNF is dominantly superparamagnetic while, MCNF is a soft ferrimagnet at 300 K. The maximum specific absorption rate (SAR) for 1 mg/mL suspension of nanoferrite powder in de-ionized water was found to be 179 W/g and 338 W/g for ZCNF and MCNF, respectively. Further, the highest hyperthermia temperature of 41.5 °C and 52 °C was achieved in 900 s at 15.98 kA/m for ZCNF and MCNF, respectively. Both ZCNF and MCNF showed good cytocompatibility with a tested concentration of 0.5 mg/mL against the human embryonic kidney HEK-293 (>75% cell viability) cell line. Additionally, simulated in-vitro treatment at an optimum magnetic hyperthermia temperature of 45 °C for 30 min in the presence of ZCNF and MCNF powder (up to a concentration of 1 mg/mL) led to suppression of ∼55% lung cancer cell lines (A549) while, in similar simulated condition the cell viability of normal HEK 293 cell lines remain unaffected. In summary, ZCNF and MCNF are appropriate therapeutic nanomaterials for magnetic hyperthermia-related cancer therapies.