Photodynamic therapy (PDT) is a palliative technique that can improve median survival with minimal invasion for cholangiocarcinoma (CC) patients. An ideal photosensitizer (PS) is critical to guarantee the efficacy of PDT. However, conventional PSs have some obvious drawbacks, such as lack of specificity and easy aggregation in aqueous media that limit their further application in the clinic. We herein fully take advantage of a red emissive aggregation-induced emission (AIE) PS to fabricate integrin αβ targeted organic AIE dots for image-guided PDT via a simple and straightforward one-step strategy. The obtained AIE dots exhibit high specificity to CC as well as excellent antitumor effect both in vitro and in vivo. Different from conventional PSs and previously reported PS-loaded nanostructures, the AIE dots do not suffer from aggregation-caused fluorescence quenching and reduction in reactive oxygen species production when the AIE PS molecules are in an aggregated state. The significant antitumor effect, as well as good biocompatibility and negligible toxicity, makes the AIE dots promising for future translational research in CC diagnosis and therapy.

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Photosensitizer (PS) serves as the central element of photodynamic therapy (PDT). The use of common nanoparticles (NPs) for PDT has typically been rendered less effective by the undesirable aggregation-caused quenching (ACQ) effect, resulting in quenched fluorescence and reduced reactive oxygen species (ROS) generation that diminish the imaging quality and PDT efficacy. To overcome the ACQ effect and to enhance the overall efficacy of PDT, herein, integrin α ν β 3 -targeted organic nanodots for image-guided PDT were designed and synthesized based on a red emissive aggregation-induced emission (AIE) PS. Methods: The TPETS nanodots were prepared by nano-precipitation method and further conjugated with thiolated cRGD (cRGD-SH) through a click reaction to yield the targeted TPETS nanodots (T-TPETS nanodots). Nanodots were characterized for encapsulation efficiency, conjugation rate, particle size, absorption and emission spectra and ROS production. The targeted fluorescence imaging and antitumor efficacy of T-TPETS nanodot were evaluated both in vitro and in vivo . The mechanism of cell apoptosis induced by T-TPETS nanodot mediated-PDT was explored. The biocompatibility and toxicity of the nanodots was examined using cytotoxicity test, hemolysis assay, blood biochemistry test and histological staining. Results: The obtained nanodots show bright red fluorescence and highly effective 1 O 2 generation in aggregate state. Both in vitro and in vivo experiments demonstrate that the nanodots exhibit excellent tumor-targeted imaging performance, which facilitates image-guided PDT for tumor ablation in a hepatocellular carcinoma model. Detailed analysis reveals that the nanodot-mediated PDT is able to induce time- and concentration-dependent cell death. The use of PDT at a high PDT intensity leads to direct cell necrosis, while cell apoptosis via the mitochondria-mediated pathway is achieved under low PDT intensity. Conclusion: Our results suggest that well-designed AIE nanodots are promising for image-guided PDT applications.