A Light-Up Probe with Aggregation-Induced Emission for Real-Time Bio-orthogonal Tumor Labeling and Image-Guided Photodynamic Therapy.

Bio-orthogonal tumor labeling is more effective in delivering imaging agents or drugs to a tumor site than active targeting strategy owing to covalent ligation. However, to date, tumor-specific imaging through bio-orthogonal labeling largely relies on body clearance to differentiate target from the intrinsic probe signal owing to the lack of light-up probes for in vivo bio-orthogonal labeling. Now the first light-up probe based on a fluorogen with aggregation-induced emission for in vivo bio-orthogonal fluorescence turn-on tumor labeling is presented. The probe has low background fluorescence in aqueous media, showing negligible non-specific interaction with normal tissues. Once it reacts with azide groups introduced to tumor cells through metabolic engineering, the probe fluorescence is lightened up very quickly, enabling rapid tumor-specific imaging. The photosensitizing ability was also used to realize effective image-guided photodynamic tumor therapy.