A self-reporting photosensitizer for inducing and in-situ monitoring lysosomal damage and cell apoptosis

Photodynamic therapy (PDT) is a desirable method to fight against cancer, because it can achieve selective ablation of tumor tissues via the control of incident light. Self-reporting PDT sensitizers that can in-situ and real -timely monitor cell viability during PDT process are promising tools for PDT. For lysosomal damage would release cathepsins B/D into cytoplasm and efficiently induce cell apoptosis, herein, we have constructed a unique self-reporting PDT sensitizer (NSLN) targeting lysosomes in living cells. NSLN was designed to equip both alkalescent unit and cationic group. And NSLN targeted lysosomes in living cells, and immigrated into nucleus after lysosomal damage and cell death. In this way, the cells viability could be facilely visualized via subcellular localization of NSLN. With the probe, the apoptosis induced by H2O2, rotenone, and paclitaxel has been suc-cessfully monitored. Furthermore, NSLN could generate large amount of reactive oxygen species and induce lysosomal damage and cell apoptosis upon light irradiation. The cell damage during PDT procedure could be also monitored with NSLN via its subcellular immigration. This work provides a novel method for monitoring PDT process and makes it possible to control phototoxicity. We believe that NSLN can be used as a powerful tool to promote the development of PDT.