Rationally Driven Drug Nonradiative Decay via a Label-Free Polyprodrug Strategy to Renew Tumor Cascade Photothermal-Chemotherapy.

Drugs are frequently used for only chemotherapy that ignores their photophysical properties that potentially endow them with other therapeutic potency. Additionally, current photothermal-chemotherapy replies on the codelivery of drugs and photothermal agents, but their spatiotemporal delivery and precise release is unsatisfactory. Herein, label-free doxorubicin (DOX) polyprodrug nanoparticles (DPNs) are formulated from disulfide bonds-tethered DOX polyprodrug amphiphiles (PDMA-b-PDOXM). Benefiting from boosted nonradiative decay of high-density DOX, significant fluorescence quenching and photothermal effects are observed for DPNs without common photothermal agents. Upon cellular uptake and laser irradiation, the heat can promote lysosomal escape of DPNs into reductive cytosol, whereupon free DOX is released to activate chemotherapy and fluorescence, achieving rational cascade photothermal-chemotherapy. The current label-free polyprodrug strategy can make full use of drugs; it provides an alternative insight to extend the therapeutic domain of drugs.