An Aptamer-Conjugated AIEgen for Targeted Bioimaging and Photodynamic Therapy of Cancer Cells

Photodynamic therapy (PDT) has emerged as a promising noninvasive treatment for cancer and other diseases. Aggregation-induced emission (AIE) photosensitizers are excellent candidates for enhancing the efficacy of image-guided PDT due to their unique properties. DNA-modified AIE luminogens (AIEgens) offer an effective approach for nucleic acid detection and biospecies sensing, but their applications in tumor cell imaging and image-guided PDT have been rarely reported. Herein, we designed a light-up probe, named ApApt, for targeted imaging and image-guided PDT of cancer cells. The probe was prepared by conjugating AIEgen with aptamer and displayed specific targeting ability to EpCAM (epithelial cell adhesion molecule)-positive cancer cells. ApApt exhibits good water solubility and shows very low emission in aqueous solution. However, it emits strong fluorescence as a result of the restricted intramolecular motion (RIM) activation of AIEgens, which is triggered by the specific binding between the aptamer SYL3C and EpCAM protein. Upon delivery to cancer cells, ApApt efficiently generates ROS for targeted PDT under light irradiation.