U‐Shaped Conjugated Oligomer‐Based Micelles as a Ratiometric Fluorescent Nanothermometer for Diverse Cellular Applications

Abstract Herein, a conjugated oligomer is reported possessing a unique U‐shaped molecular geometry, which significantly affects the intramolecular charge transfer and modulates the fluorescence properties. Upon excitation, it displays blue/red dual emission, which is very sensitive to the polarity and viscosity of solvents. After being incorporated into Pluronic F127 micelles, a dramatic fluorescence enhancement is found in its red emission (up to 27‐fold) along with a stable blue emission at elevated temperature. Accordingly, the emissive micelles are successfully explored as a reliable ratiometric nanothermometer both in solution and in cellular environment. Moreover, compared to nanoparticle counterpart prepared by classical nanoprecipitation, the conjugated oligomer/F127 micelles exhibit a remarkable improvement in photo‐triggered reactive oxygen species (ROS) generation efficiency and photodynamic killing behavior on cancer cells. The current study will help researchers to further understand the structure–property relationship of π‐conjugated fluorophores and design various nanomaterials with promising potential for simultaneous diagnostic and treatment on cancers.