Extracellular vesicles (EV) are complex nanoparticles required for the intercellular transfer of diverse biological cargoes. Exploitation of EV as advanced drug delivery systems has sparked general interest both in academia and industry for the treatment of a multitude of diseases including cancer. However, the clinical application of EV-based therapeutics is hampered by the lack of knowledge on their (sub)cellular interactions and the components that affect these interactions, as well as their study in mainly two-dimensional monolayer culture systems. Building upon the preliminary data and expertise obtained during my PhD, I will study how the biopharmaceutical production process and exposure to human plasma proteins define biomolecular corona formation, using in-house developed recombinant EV (rEV) as a model system for EV-based therapeutics. Next, I will provide unprecedented insights in the impact of biomolecular corona formation on (sub)cellular interactions in patient derived tumor fragments with preserved tumor microenvironment architecture using state-of-the-art technologies including light sheet fluorescent microscopy and super resolution microscopy. Finally, I will modulate rEV by surface modification to optimize and direct (sub)cellular interactions. I am confident that the technological advances in combination with the biological understanding gained in my project will rEVolutionize the clinical application of EV-based therapeutics.