Superparamagnetic iron oxide/oleic acid nanoparticles bearing lipid-like organosilicon N-(2-hydroxyethyl)-1,2,3,4-tetrahydroisoquinoline derivatives have been synthesized with the aim of their potential biomedical application. X-ray diffraction analysis, Dynamic light-scattering measurements, method of magnetogranulometry and some others have been employed to investigate the morphology and properties of the nanoparticles synthesized. The magnetic core diameter of mixed covered nanoparticles ranged between 4.8 and 9.6nm. The magnetization analyses showed that the particles are superparamagnetic at room temperature. In vitro cell cytotoxicity and intracellular NO generation caused by the water magnetic solution of nanoparticles possessing cytotoxic organosilicon heterocyclic choline analogue, namely N-(2-dimethyl-n-hexadecylsiloxyethyl)-N-methyl-1,2,3,4-tetrahydroisoquinolinium iodide, was examined in relation to monolayer human fibrosarcoma (HT-1080) and mouse hepatoma (MG-22A) tumour cell lines and normal mouse fibroblasts (NIH 3T3). The biological studies have revealed its selective cytotoxicity in tumour cells and strong effect on MG-22A cell morphology. Incorporation of the synthesized nanoparticles into cells was observed