Biomimetic black phosphorus quantum dots-based photothermal therapy combined with anti-PD-L1 treatment inhibits recurrence and metastasis in triple-negative breast cancer

Background Triple-negative breast cancer (TNBC) is a highly aggressive malignant disease with a high rate of recurrence and metastasis, few effective treatment options and poor prognosis. Here, we designed and constructed a combined photothermal immunotherapy strategy based on cancer cell membrane-coated biomimetic black phosphorus quantum dots (BBPQDs) for tumor-targeted photothermal therapy and anti-PD-L1 mediated immunotherapy. Results BBPQDs have good photothermal conversion efficiency and can efficiently target tumor cells through homologous targeting and tumor homing. Under near infrared irradiation, we found that BBPQDs kill tumors directly through photothermal effects and induce dendritic cells maturation. In vivo studies have confirmed that the combined photothermal immunotherapy strategy displays a stronger antitumor activity than anti-PD-L1 monotherapy. In addition, BBPQDs-mediated photothermal therapy in combination with anti-PD-L1 treatment inhibit tumor recurrence and metastasis by reprograming the immunosuppressive tumor microenvironment into an immune-active microenvironment, and promoting the local and systemic antitumor immune response. We further found that the combined photothermal immunotherapy strategy can produce an immune memory effect against tumor rechallenge. Conclusions This study provides a novel therapeutic strategy for inhibiting the recurrence and metastasis of TNBC, with broad application prospects.