Biocompatibility and potential functionality of lanthanum-substituted cobalt ferrite spinels

Bulk and nanostructurized lanthanum-cobalt spinels have attracted a lot of interest from researchers, due to their unique physical and chemical properties as well as functionalities, which are interesting for biomedical and electronic industries. In this manuscript we show that introducing small lanthanum (La3+) content can tune magnetic, electronic and cytotoxic properties of the CoFe2_xLaxO4 system (x & LE; 0.1). The mechanisms of the tuning are comprehensively studied by theoretical electronic structure calculations; spectroscopic methods (FTIR, Mo & BULL;ssbauer, XAS); structural and microstructural research; magnetometry; and cytotoxic viabilities of normal and cancer cells. It was found that the mechanism originate mainly from the complex exchange interaction of the 3d states of cations with 2p states of oxygen caused by mixing of the metals over the tetragonal and octahedral positions. For synthesized CoFe2_xLaxO4 nanoparticles (NPs) in vitro studies of toxicity on the tested cell lines (human Hs27 fibroblasts, A375 melanoma, Nthy-ori 3-1 thyrocytes, and FTC-133 thyroid cancer cells) revealed that CoFe2_xLaxO4 NPs have high impact on cancer cells, while their toxicity towards normal cells is significantly lower. Along to soft magnetic properties this is a key factor for functionalization.