Versatile Red Blood Cells for Triple‐Negative Breast Cancer Treatment via Stepwise Photoactivations

Phototherapies have many advantages for triple‐negative breast cancer (TNBC) treatment. However, their effects are often limited by short blood circulation time, poor tumor selectivity and weak penetration of phototherapeutic agents, and tumor hypoxia. For overcoming these limitations, a versatile biomimetic system is developed based on red blood cells (RBCs). Photothermal agent new indocyanine green (IR820) is conjugated with the cell/tissue‐penetrating TAT peptide and further efficiently encapsulated into the intact RBCs by crossing cell membranes to realize the long blood circulation. Meanwhile, cyclic RGD peptide (cRGD) is linked to the surfaces of RBCs through phospholipid insertion to obtain tumor vessel‐targeting ability. Photosensitizer temoporfin (mTHPC) is next loaded into the membranes of RBCs by spontaneous transferring. The acquired biomimetic system (cRGD‐RBC@mTHPC/TAT‐IR820) exhibits potent photodynamic performance upon 652 nm laser irradiation with the facilitation of oxyhemoglobin, which could not only trigger TAT‐IR820 release but also destroy tumor vessels. TAT‐IR820 penetrates deeply into tumor tissue via the mediation of TAT peptide, exerting greatly promoted photothermal ablation against TNBC upon 808 nm laser irradiation. In situ generated tumor antigens further induce robust immune responses to suppress TNBC recurrence and metastasis. In summary, this study provides a versatile biomimetic system for comprehensive TNBC treatment via stepwise photodynamic and photothermal activations. Red blood cells with surface‐modification of cRGD are used for co‐loading and targeted delivery of photothermal agent IR820 and photosensitizer temoporfin. Upon stepwise photoactivations at 652 and 808 nm, this biomimetic system exerts photodynamic and photothermal performances, and hence efficiently suppresses the growth and metastasis of triple‐negative breast cancer by local tumor ablation and systematic immune activation.