Nowadays, nanotechnologies are ones of the newest technologies, which a wide range of applications such as in medicine, biotechnology, electronics, energy or sensing. However, the efficiency of nanomaterials or at least their proper application in oncology or in wastewater treatment in order to remove the micropullants contained in it has not been fully proved yet. In this thesis there have been studied different types of selected nanomaterials and their effects on microorganisms such as bacteria or tumor cells. The obtained results show that some of the tested nanomaterials have low inhibitory effects on studied microorganisms. There was also showed that some of the tested nanomaterials had an inhibitory effect on tumor cells.