Cold atmospheric plasma (CAP) is gaining interest for cancer treatment, although the application is still in its early stages. Besides direct CAP treatment of cancer cells, plasma can also be used to treat liquids, which appear to have similar anti-cancer effects as the plasma itself. These plasmatreated liquids (PTL) are very promising for cancer treatment, as they can be more generally used, e.g. they might be directly injected into tissue of patients. However, the selectivity of PTL treatment towards cancer cells, leaving normal cells undamaged, is only scarcely explored. This is exactly the focus of this project. We will try to define which cancer cell types are more (or less) sensitive towards PTL treatment and how selectivity towards cancer cells can be promoted. For this purpose, we will link the chemical composition of the PTL (reactive oxygen, nitrogen and chlorine species) with the selectivity in cancer vs. normal cell cytotoxicity, to know which species promote this selectivity (WP1). In parallel, we will develop a 0D and 2D computational model to simulate the plasma-liquid interactions (WP2+3). With the knowledge obtained in WP1, we can use the models to elucidate which plasma treatment conditions enhance the selectivity. Then, we will apply these conditions in the patient cell experiments to optimize the selectivity (WP4). Finally, we will also strive to unravel the underlying mechanisms of this selectivity in the cell experiments (WP4).