Sulfonyl-substituted zinc phthalocyanine micelles with long-lived triplet states enable durable photodynamic immunotherapy.

Pluronic® P123 micelles stabilized a sulfonyl-substituted zinc(ii) phthalocyanine, prolonged its triplet-state lifetime, and preserved ROS photochemistry under biologically relevant conditions. Pharmacokinetic-guided C-PDT at a 24 h DLI remained insufficient as monotherapy, whereas combination with PD-L1 blockade produced durable tumor control. Rechallenge experiments after PDT additionally revealed complete long-term antitumor immune memory.