Real-Time Monitoring of DNA Origami-Cell Interactions via Single Particle Tracking.

Due to the unique spatial addressability of DNA origami, targeting ligands can be specifically positioned onto the surface of the nanostructure, constituting an essential tool for studying ligand-receptor interactions at the cell surface. While the design and ligand incorporation into DNA origami nanostructures is well-established, the study of dynamic interactions with cell surfaces is still in the explorative phase, where an in-depth fundamental understanding of the molecular interaction dynamics remains underexplored. This study uniquely captures real-time encounters between DNA origami and cells in situ using single particle tracking (SPT). We functionalized DNA nanorods (NRs) with antibodies or aptamers specific to the epidermal growth factor receptor (EGFR) and used them to target EGFR-overexpressing cells. SPT data revealed that ligand-coated NRs selectively bind to the receptors expressed in target cancer cells, while non functionalized NRs only display negligible cell interactions. Furthermore, the effect of ligand density is explored on the DNA origami, which revealed that aptamer-decorated NRs exhibit nonlinear binding characteristics, whereas this effect in antibody-decorated NRs is less pronounced. This study provides new mechanistic insights into the fundamental understanding of DNA origami behavior at the cell interface, with unprecedented spatiotemporal resolution, aiding the rational design of ligand-targeted DNA origami for biomedical applications.