Fig. 1

Preparation of characterizations of PPF NPs. a Schematic illustration showing the mechanism behind PPF NPs enabled immunotherapy. The PPF conjugate contains two nanocompartments, which are FRT and PLGA NPs. These two compartments are separately encapsulated with ZnF₁₆Pc and NLG919, and covalently linked. Under photo-irradiation, ZnF₁₆Pc is activated, leading to cancer cell death and release of tumor associated antigens. Meanwhile, NLG919 causes the suppression of IDO and restored the Trp/Kyn balance; this results in reduced tumor infiltration of Tregs and MDSCs and increased cytotoxic T cell activity, leading to enhanced antitumor immunity. b Hydrodynamic sizes of FRT, NLG919@PLGA and PPF NPs, measured by DLS. c Zeta potential of FRT, NLG919@PLGA and PPF NPs