Silica/potassium ferrite nanocomposite: Structural, morphological, magnetic, thermal and in vitro cytotoxicity analysis

Highlights: • Silica coating on potassium ferrite nanoparticles is reported. • Their structural, morphological, thermal behaviour is studied and compared. • Both bare and coated nanoparticles are superparamagnetic and biocompatible. -- Abstract: The coating of silica on potassium ferrite (KFeO2) nanoparticles has been reported in the present study. The X-ray diffraction pattern revealed the formation of orthorhombic structure of bare potassium ferrite nanoparticles, which was also retained after the silica coating, along with a broad band near 2θ ∼ 20–25° pertaining to the presence of amorphous silica. The size of bare and coated potassium ferrite nanoparticles was found to be 4–8 nm and 10–22 nm, respectively, as observed from transmission electron microscope. The presence of silica was also revealed by the Fourier transform infrared spectrum and high resolution transmission electron microscope. In vibrating sample magnetometer analysis, both bare as well as coated potassium ferrite nanoparticles exhibited superparamagnetic behaviour with magnetic saturation values, 49.01 and 21.17 emu/g, respectively. Dose-dependent cellular toxicity was observed in the in vitro MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole) – assay study on Jurkat cells, where both bare as well as silica coated nanoparticles exhibited non-toxicity below 250 μg/ml. An augmentation of cell viability was observed in case of silica coated potassium ferrite nanoparticles. The nanosize, superparamagnetic behaviour and enhanced cell viability make silica coated potassium ferrite nanoparticles a potential claimant for biomedical applications