In order to use nanoparticles with medical applications is necessary their dispersion and a low toxicity. To avoid or decrease the toxicity of the magnetic nanoparticles inside of the cells, it is necessary functionalized covering particles with organic or inorganic compounds. The stability of this functionalization depends on the type of interaction between the nanoparticle surface and the functional group covering. At least two types of interaction might be consider, covalent bonding and a weaker interaction. Depending on these interactions the stability and toxicity of the nanoparticles could be different. The main aim of this proposal is to measure the vibrational spectra in order to obtain information on the nature of the interaction between the nanoparticle and the functionalized molecules