Dual-drug loaded manganese dioxide nanoparticles coated with bacterial outer-membrane vesicles for chemo-immunotherapy in lung cancer

Lung cancer is the most leading cause of cancer death. Traditional chemotherapy has unavoidable drawbacks of nonspecific tumor targeting, high toxicity, and poor therapeutic efficiency. Nanocarriers can achieve accurate delivery and reduce adverse reactions of drugs, which have received extensive attention. In this work, hollow manganese dioxide (HMnO₂) nanoparticle (NP) that is highly responsive to tumor microenvironment, was simultaneously loaded with paclitaxel (PTX), a chemotherapy drug, and imiquimod (R837), a toll-like receptor 7 agonist. Those NPs were then coated with bacterial outer-membrane vesicles (OMVs-HMnO₂@PTX + R837 NPs), whose surface proteins could act as tumor-specific antigens. The obtained nanovaccine inherited superior tumor-targeting capacity of OMVs and promoted retention in tumors. As a result, intravenous injection of the nanovaccine led to remarkable tumor growth inhibition. Furthermore, we found that the nanovaccine effectively boosted dendritic cells maturation and increased cytotoxic T lymphocytes infiltration. Taken together, these results demonstrated the great potential in applying OMVs-enveloped nano-activator in cancer chemo-immunotherapy.