Phototherapy with theranostic Co3O4 nanoplates eliminates metastatic solid tumors by activating systemic tumor immunity and memory

Solid tumors develop complex and heterogenous immune suppressive environment, and thus are frequently resistant to existing immunotherapies. To effectively treat malignant solid tumors especially the metastatic ones, it is critical to develop strategies to activate tumor immunity by reversing the tumor-induced immune suppression. Here, we describe a near-infrared (NIR) responsive porous Co3O4 nanoplates (pCo3O4 NPs) that can deliver a single laser triggered photothermal/photodynamic combination therapy. This phototherapy can eliminate the treated primary tumors and suppress distal tumors by disrupting the immune suppressive microenvironment and activating systemic tumor-specific immunity. The single cell sequence analysis of intra-tumoral immune populations demonstrated that this phototherapy can activate both intra-tumoral and systemic immune cells.