Photo-Reduction with NIR Light of Nucleus-Targeting Pt IV Nanoparticles for Combined Tumor-Targeted Chemotherapy and Photodynamic Immunotherapy.

The development of Pt IV prodrugs which are selectively reduced within cancerous cells into their Pt II therapeutically active species has received increasing attention within the last decade. Despite recent research progress, the majority of investigated compounds are excited using ultraviolet or blue light. As the light penetration depth is low at these wavelengths, the treatment of deep-seated or large tumors is limited. To overcome this limitation, herein, the example of Pt IV -functionalized nanoparticles that could be excited within the NIR region at 808 nm is reported. The polymer backbone which can self-assemble into nanoparticles was functionalized with Pt IV complexes for chemotherapy, photosensitizers for photodynamic immunotherapy, and nucleus/cancer-targeting peptides. Upon irradiation, the Pt IV center is reduced to Pt II and the axially coordinated ligands are released, presenting a multimodal treatment. While selectively accumulating in tumorous tissue, the nanoparticles demonstrated the ability to eradicate a triple-negative breast cancer tumor inside a mouse model.