Surfactant-chaperoned donor-acceptor-donor NIR-II dye strategy efficiently circumvents intermolecular aggregation to afford enhanced bioimaging contrast.

Fluorescence emission in the near-infrared-II (NIR-II) optical window affords reduced autofluorescence and light scattering, enabling deep-tissue visualization for both disease detection and surgical navigation. Small-molecule NIR-II dyes are preferable for clinical bioimaging applications, as the flexibility in their molecular synthesis allows for precise control of their optical and pharmacokinetic properties. Among the various types of dye, donor-acceptor-donor-based (D-A-D) dyes demonstrate exceptional photostability, whereas the frequently used PEGylation approach does not keep their intrinsic brightness enough in water environments due to their inherent effect of self-assembly.