NRP1 and neoplasm: To overcome the blood–brain barrier permeation restriction, the authors conceived to associate the natural biocompatibility of the exosomes with appropriate surface functionalization; this led to neuropilin-1 (NRP-1)-targeting exosomes, useful as a theranostic platform, since NRP-1 is a transmembrane glycoprotein overexpressed by glioma cells and tumor vasculature [100].