Aptamers with Tunable Affinity Enable Single-Molecule Tracking and Localization of Membrane Receptors on Living Cancer Cells.

Tumor cell-surface markers are usually overexpressed or mutated protein receptors for which spatiotemporal regulation differs between and within cancers. Single-molecule fluorescence imaging can profile individual markers in different cellular contexts with molecular precision. However, standard single-molecule imaging methods based on overexpressed genetically encoded tags or cumbersome probes can significantly alter the native state of receptors.