Electric discharges in liquids are promising for the production of Nanoparticles (NPs) with high yields (up to 17g/h). Moreover a wide range of nano-objects can be created, from 1 or 2D materials to core-shell nanoparticles. However, the plasma-material interactions that give rise to NPs remain complex and incompletely understood. The present talk will review the progresses and challenges in plasma diagnostics and their interactions with materials.