Higher-Order Clustering of Receptors Real-Time Projected by Plasmon-ruler on the Single Live Cell.

Higher-order receptor clustering on cell surfaces as an artificial switch becomes increasingly pivotal for signal transduction and targeted therapy, yet its real-time and long-term tracking remains limited by photobleaching and endpoint-only assays. Here, we develop a color-changing plasmon-ruler via DNA-guided quantized assembly of small gold nanoparticles (GNPs) onto a large GNP core. Coupling aptamer specificity with plasmonic clustering optics, this system enables real-time projection and in situ modulation of heterotypic MET and TfR higher-order clustering at the single-cell level. Under dark-field microscopy (DFM), controllable GNP assembly projects continuous spatiotemporal receptor transitions from loose to dense states, with plasmon scattering converted into pseudocolors for direct visualization. Biological assays confirmed a strong correlation between color changes and the degree of clustering, reducing Met and Akt phosphorylation by ∼2.3- and ∼1.5-fold, and decreasing cell migration from 71.6% to 50.1%. This plasmon-ruler establishes a new strategy for multidimensional imaging of receptor clustering dynamics.