Outside Front Cover: Ligand‐Directed Molecular Beacons as Turn‐On Fluorescent Probes for Sensing Cell‐Surface Receptor‐Ligand Interactions

Multivalent, ligand-directed molecular beacons undergo conformational switching at the cell surface, enabling fluorescence turn-on detection of membrane receptors. In the Research Article e3191334, David Margulies and co-workers reported the modular design of these probes enables tunable receptor selectivity, binding affinity, and emission properties, providing a versatile platform for wash-free receptor imaging, detecting receptor–inhibitor interactions, and evaluating therapeutic antibodies.