In this study, we analysed the influence of PEI-coated magnetic NPs designed for biotechnological applications and industrial SiO<sub>2</sub>, TiO<sub>2</sub> N and TiO<sub>2</sub> P25 NPs on intracellular localization and solubility of fused in farcoma (FUS) and TAR-DNA binding protein 43 (TDP-43) that are important pathological hallmarks of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD).