Real‐Time Discrimination of Parallel Single‐Cell Exocytotic and Exosome Catecholamine Signaling by Multichannel Hollow Nanoelectrodes

Chemical communication in single cells often involves multiple vesicle release pathways that can carry overlapping messenger molecules. However, existing methods cannot discriminate between these pathways simultaneously under matched conditions, making their intrinsic relationship difficult to resolve. Here we establish a multichannel hollow carbon nanoelectrode-based strategy for real-time discrimination of classical exocytosis and exosome-associated release. Distinct electrochemical signatures generated within the hollow geometry enable pathway resolution, while the multichannel architecture expands effective sampling coverage over the cell surface and improves event capture efficiency. Using this approach, we show that the two catecholamine signaling routes remain active under environmental perturbation but exhibit non-compensatory changes in release activity. Under cargo-loading disruption, classical exocytosis retains reduced catecholamine output, whereas exosome-associated release persists but becomes largely chemically silent. These findings uncover a previously inaccessible chemically silent state of exosome-associated release and reveal that cells can preserve a release pathway while selectively reshaping its chemical consequence. More broadly, this work shows that parallel release routes can convey fundamentally different chemical information under the same cellular conditions and establishes a general strategy for studying pathway-specific chemical regulation in other secretory systems.