Devising Biocompatible, NIR-Activated Helical Pyroptosis Agents via 𝛑-Twisting Strategy for Promoting Antitumor Immunity.

Specifically controlling cell pyroptosis is advantageous for oncotherapy as it allows simultaneous ablation of primary tumors and activation of immunogenicity of tumor environment. Herein, a facile and robust strategy is presented to construct efficient NIR-activated helical pyroptosis agents (PyroAs) with negligible dark cytotoxicity. It is demonstrated that the construction of four intramolecular B-X bonds (X = O or N) within the BODIPY chromophore enforces a significant twisting of its π-conjugation, yielding a variety of helical BD molecules with desired high photosensitivity and negligible dark toxicity. A robust approach is established to extend BD into the near-infrared (NIR) region through site-selective incorporation of an electron-withdrawing ester moiety. It is also proved that targeted delivery of the NIR-activated BD-ER to the endoplasmic reticulum (ER) specifically activates pyroptosis pathway by equipping it with an ER-targeting moiety. Finally, the favorable biocompatibility, excellent antitumor efficacy, and remarkable systematic immune response of this unique NIR-activated helical PyroAs are shown in vivo, demonstrating its potential application in solid tumor immunotherapy.