A Carrier-free Peptide Co-assembled System with Synergistic Antitumor Effect Combines Immunotherapy and Sonodynamic Therapy

Blocking programmed cell death ligand 1 (PD-L1) in tumor cells is an effective therapy strategy to achieve immune system activation for tumor therapy, however only a few patients can benefit from it. Development of synergistic therapy with checkpoint PD-L1 blockade immunotherapy is beneficial to enhance antitumor effect. Herein, we constructed a carrier-free system EH@Ag2S co-assembled by peptide nanofiber and Ag2S nsanoparticles to achieve a superadditive (1 + 1 > 2) antitumor effect. EH nanofiber can block PD-L1, and Ag2S can produce reactive oxygen species (ROS) under ultrasound irradiation and induce cell apoptosis. Further, in vivo mice experiment also confirmed the high efficiency of this carrier-free co-assembled system in successfully inducing anti-tumor response while inhibiting tumor growth. We believe that this highly bioavailable and multifunctional therapeutic system may become a promising nanoplatform for tumor therapy.