关键词:
image guidance
photosensitizer
photodynamic therapy
two-photon
tumor-targeting
摘要:
Fluorescence image-guided photodynamic therapy (PDT) enables real-time monitoring of photosensitizer biodistribution and metabolism for optimized treatment timing. However, its application remains limited, in part, by the reliance on high-end imaging systems. To address this, we designed three novel small-molecule photosensitizers (TTNb, TTAn and TTPh) based on a 2-vinylbenzoic acid scaffold, functionalized at the 5-position with nitro, amino, or hydrogen groups, respectively. Strikingly, replacing the nitro group with amino or hydrogen switched their aggregation behavior from aggregation-induced emission (AIE) to aggregation-caused quenching (ACQ accompanied by a red-to-green fluorescence shift and subcellular relocation from liposomes to lysosomes. These findings not only establish key design principles for developing ratiometric nitroreductase probes-a currently underexplored class of sensors-but also enable systematic comparison between AIE and ACQ photosensitizers. Among these compounds, TTAn exhibited superior cellular uptake (2800 times higher than the clinical photosensitizer Ce6 in Eca-109 cells specific lysosomal targeting, balanced reactive oxygen species (singlet oxygen/superoxide anion) generation, and intense fluorescence. Under white light irradiation, TTAn achieved an exceptional IC50 of 21 nM, surpassing Ce6 by 50-fold. Notably, TTAn produced strong fluorescence in mice tumors under both one- and two-photon excitation, detectable using conventional imaging tools (e.g., smartphones, DSLR cameras) or even visible to the naked eyes, confirming its outstanding tumor specificity. Leveraging these advantages, TTAn enabled successful image-guided two-photon PDT in Eca-109 tumor-bearing mice with just a single treatment, demonstrating potent therapeutic efficacy and biosafety. This work provides a strategic blueprint for developing small-molecule theranostic agents that operate without complex fluorescence imaging systems. (PDT) 2- 5(TTNb,TTAn, TTPh). TTAn: