Cell-to-cell communication pathways coordinate cellular functions in multicellular organisms. Cells that are nearest neighbours can communicate through specific interactions between ligand and receptor proteins present in their respective cell membranes. The objective of this research program is to address the hypothesis that the physical context of the ligand/receptor interaction contributes to defining the fundamental mechanisms of action of cell-to-cell communication pathways and their cellular outcomes.The research program relies on the development of tools that provide well-defined physical inputs to cells, not confounded by simultaneous changes in chemical inputs. Therefore, beyond state-of-the-art developments in nanotechnology are here integrated with cell biology. In particular, DNA origami technology is applied to the development of ligand nanoclusters with customized spatial organization and mechanical properties. These ligand nanoclusters are used to probe the roles of physical properties of the ligand presentation on the activation of intracellular signalling pathways.We will focus on the ephrin/Eph cell-to-cell communication pathway, which regulates embryonic development and the homeostasis of adult organs. ephrin/Eph signalling is commonly disrupted in cancer, showing tumour suppressing or tumour promoting character. The mechanisms that generate the diversity of outcomes of the ephrin/Eph pathway are largely unknown. We will use DNA origami/ephrin ligand nanoclusters to investigate whether the spatial organization and mechanical properties of ephrin ligand assemblies impact Eph receptor function and contribute to generating diversity in the pathway. Our novel approach is readily transferrable to the study of other signalling pathways. We aim to generate a knowledge foundation for the roles of mechanotransduction, the conversion of physical to biochemical signals, in cell-to-cell communication mediated by membrane-bound ligands and receptors.