Even though a number of different in vitro fusion assays have been developed to analyze protein mediated fusion, they still only partially capture the essential features of the in vivo situation. Here we established an in vitro fusion assay that mimics the fluidity and planar geometry of the cellular plasma membrane to be able to monitor fusion of single protein-containing vesicles. As a proof of concept, planar pore-spanning membranes harboring SNARE-proteins were generated on highly ordered functionalized 1.2 μm-sized pore arrays in Si3N4. Full mobility of the membrane components was demonstrated by fluorescence correlation spectroscopy. Fusion was analyzed by two color confocal laser scanning fluorescence microscopy in a time resolved manner allowing to readily distinguish between vesicle docking, intermediate states such as hemifusion and full fusion. The importance of the membrane geometry on the fusion process was highlighted by comparing SNARE-mediated fusion with that of a minimal SNARE fusion mimetic.

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conductor (SC) nanorods (NRs) with Type-II heterojunctions that exhibit a large Quantum Confined Stark Effect (QCSE) at room temperature (1). For using these NRs as voltage sensors, however, one needs to impart them with membraneprotein like properties so that they can be stably inserted into the membrane. We report here spontaneous insertion of SC NRs into liposomes and cell membranes by functionalizing them with specially designed peptides. We provide evidences for insertion from cryo transmission electron microscopy (TEM) and polarized light microscopy. We also report on first attempts to sense membrane potential with these particles with single-particle sensitivity. With further improvements, SC NRs could potentially be used to study signals from whole neural networks in a large field-of-view. Moreover, successful implementation of SC NRs would allow for the analysis of voltage signals at the nano-(single synapse-) scale.