Molybdenum and tungsten nanoparticles synthesized at the Jožef Stefan Institute possess a unique form and degree of anisotropy, with confirmed antibacterial activity. In order to use nanomaterials for medical purposes it is necessary to demonstrate that once in contact with live tissue they do not cause tissue damage or allergic reaction, ie they do not induce an inflammatory response. Accordingly, it is necessary to determine the cytotoxicity of molybdenum and tungsten nanoparticles in human cells. Within this project we aim to investigate the biocompatibility of molybdenum and tungsten nanoparticles in human cells, ie examine their cytotoxicity and potentials to stimulate inflammatory response in human cells.