Synergistic photothermal and magnetothermal heat generation with Sc-doped iron oxide nanoflakes: a platform for potential bimodal tumor therapy

Enhancement of specific absorption rate (SAR) of iron oxide (Fe3O4) is crucial for ensuring selectivity of hyperthermia tumor therapy, yet both magnetothermal and photothermal approaches endure shortcomings i.e., high dosage and laser power densities, that compromise therapeutic efficacy. This work reports the Scandium (Sc) doped Fe3O4 nanoflakes synthesized by sol-gel route with superior heat generation properties enabling bimodal tumor therapy. The novel $$ {\text{Sc}}_{{0.05}} \left[ {{\text{Fe}}^{{2 + }} {\text{Fe}}^{{3 + }} _{{1.95}} } \right]{\text{O}}_{4} $$ nanoflakes superstructure exhibits pronounced optical extinction and a high saturation magnetization of 90.33 emu/g, arising from lattice expansion and enhanced magnetic exchange coupling. Photothermal conversion efficiency reached 66.84%, while SAR value under magnetic field (32 kA/m, 100 kHz) peaked at 1311.24 W/g (intrinsic loss power (ILP): 11.34 nHm2/kg). Under 808 nm laser exposure (2 W/cm2), photothermal SAR reached to 3480.84 W/g and with combined bimodal (LASER + AMF) heating the SAR synergically boosted to 11857.53 W/g due to temperature modulated magnetic and optical relaxation supporting each other. The material exhibits excellent biocompatibility and in vitro tumor ablation with A375 cell line using small (1 mg/mL) dosage under minimal magnetic field and laser parameters.