<i>In Situ</i> Ultrasound-Triggered Bioluminescence for Combined Sono/Photodynamic Immunotherapy

Sono-photodynamic therapy (SPDT) integrates the advantages of sonodynamic therapy (SDT) and photodynamic therapy (PDT), showing great potential for the minimally invasive treatment of malignant tumors. Nevertheless, the effectiveness of sensitizers in PDT is often limited by insufficient light penetration, restricting the synergistic therapeutic effects of SPDT. Herein, we present a controllable strategy using <i>in situ</i> ultrasound-triggered bioluminescence for enhanced SPDT. This method utilizes a mechanosensitive bioluminescent protein composed of the mechanosensitive channel of large conductance (MscL) and the aequorin (AEQ) photoprotein. Upon ultrasound stimulation, MscL responds to mechanical force by inducing Ca²⁺ influx, which subsequently activates AEQ to oxidize a luminogenic substrate and generate bioluminescence. By leveraging ultrasound and its associated bioluminescence, the natural sono-photosensitizer, Chlorin e6 (Ce6), exhibits efficient sono-/photocytotoxicity, induces immunogenic cell death, and synergistically enhances the antitumor immune response. This ultrasound-triggered SPDT not only suppresses primary tumor growth and metastasis but also induces a long-term immune memory to resist tumor rechallenge. The integration of SPDT with immune activation forms a multimodal "sono-photo-immuno" platform for in situ breast tumor treatment and simultaneously prevents tumor recurrence after tumor resection. These findings showcase our platform as a versatile tool for the development of more effective cancer therapies.