Peptidomimetic Polymer With Conformation‐Coded Hierarchical Assembly for Visualizing Biodistribution

ABSTRACT Directly encoding local physicochemical information into an intrinsically self‐referenced fluorescence signal remains a major challenge in bioimaging. Here, we report an aliphatic peptidomimetic polymer system whose luminescence is programmed through conformation‐directed hierarchical assembly. β‐sheet‐like and random‐coil conformations direct self‐assembly into rigid nanotubes and isotropic vesicles, respectively, with distinct emission profiles. At elevated local concentrations, the nanotubes undergo higher‐order assembly into spherical superstructures exhibiting a J‐aggregate‐like red‐shifted optical response, with a pronounced blue‐to‐orange color transition and emission extending into the near‐infrared region. We exploit this intrinsic concentration‐dependent color response for multicolor organelle imaging in living cells and for noninvasive, visually interpretable, semiquantitative mapping of polymer biodistribution in living animals. By converting local concentration into emission hue rather than absolute intensity, this work establishes a new design principle for self‐referenced optical imaging, with potential applications in biosensing, quantitative bioimaging, and drug delivery.