NIR/ROS‐Responsive Black Phosphorus QD Vesicles as Immunoadjuvant Carrier for Specific Cancer Photodynamic Immunotherapy

Abstract 2D black phosphorus (BP) nanosheets and BP quantum dots (BPQD), as two main material styles of BP, are widely used in the biomedical filed. However, few stimuli‐responsive BP nanocarriers are reported to meet the need of nanomedicine. Herein, near‐infrared region/reactive oxygen species (NIR/ROS) sensitive BPQD vesicles (BPNVs) are prepared by self‐assembly of amphiphilic BPQDs grafted with polyethylene glycol and ROS sensitive poly(propylene sulfide) (PPS). BPNVs exhibit enhanced photo‐absorption in the NIR region, and have high loading efficiency of immunoadjuvant CpG oligodeoxynucleotides (CpG ODNs) in the cavity of the BPNVs. Upon NIR laser irradiation, high levels of ROS are generated from BPNVs to trigger the change of hydrophobic PPS to hydrophilic polymers, leading to disassembly of the vesicles to BPQDs. In this manner, the BPNVs show synergistic photodynamic therapy combined with immunotherapy, due to simultaneous release of small BPQDs with deep tumor penetration and CpG with enhanced immunotherapy. The BPNVs‐CpG achieves potent photodynamic immunotherapy in vivo, in addition to block distant tumor growth and metastasis.