Folic acid-conjugated magnetic-luminescent nanocomposites from Mn_0.8Fe_2.2O₄ and GdVO₄:Dy³⁺ with efficient heat generation and cytocompatibility in MDA-231 cell lines

Silica-coated magnetic-luminescent nanocomposites, obtained from Mn_0.8Fe_2.2O₄ and near-white emitting GdVO₄:Dy³⁺, reported in this work for possible application in combined imaging and magnetic fluid hyperthermia. Folic acid functionalization of the nanocomposite was further achieved for enhanced tumor affinity since folate receptors are overexpressed in cancer tissues. The nanocomposite showed the cubic-tetragonal biphasic structure corresponding to the cubic Fe₃O₄ and tetragonal GdVO₄ phases. The compositions and surface modifications were confirmed by infrared spectroscopy. The formation of agglomerated nanoparticle was observed from the transmission electron microscopy comprising of particles in the 20-nm size range. Brilliant near white emission can be seen from the nanocomposites upon excitation at 287 nm. The induction heating analysis was performed at the alternating magnetic field strengths of 2.15 × 10⁶ kAm⁻¹ s⁻¹, 3.05 × 10⁶ kAm⁻¹ s⁻¹, and 4.58 × 10⁶ kAm⁻¹ s⁻¹. The MTT assay revealed that the nanocomposite exhibits 50% cell viability towards MDA-231 breast cancer cell line. Thus, these magnetic-luminescent nanocomposites will have potential applications for magnetic fluid hyperthermia and optical imaging.