We present a strategy to expand anti-Stokes shifting from far red to deep blue region in metal-free triplet-triplet annihilation upconversion (TTA-UC) and demonstrate their utility in in vivo titrating anticancer prodrug photorelease. This new TTA system has robust brightness and the longest anti-Stokes shifting among all the report TTA systems. Benefiting from these properties, we developed TTA core-shell-structured prodrug delivery capsules that are able to operate with a low power density far red-LED light. These contain mesoporous silica nanoparticles preloaded with TTA molecules as the core and amphiphilic polymers encapsulating anti-cancer prodrug molecules as the shell. When stimulated by far red light, the intense TTA upconversion blue emssison in our system activated the anticancer prodrug molecules and showed effective tumor growth inhibition in vivo. In particular, In combination with PD-1 check-point blockade anti-body,the nanocapsules are found to be highly effective against metastasis 4T1 tumor. In sum, in this study, we not only provide a simple solution to break through these key bottlenecks in the field of upconversion by creating the smallest and brightest organic TTA-UCNPs with surface modifications, but also provide a paradigm for metastatic cancer treatment in combination with cancer immunotherapy.

Design near infrared absorbing triplet-triplet annihilation nanoparticles and application in tumor immunotherapy

2019 Fall National Meeting

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