Sequential pH/GSH-responsive stealth nanoparticles for co-delivery of anti-PD-1 antibody and paclitaxel to enhance chemoimmunotherapy of lung cancer.

Intravenously administered nanoparticles (NPs) often bind with plasma proteins, forming the protein corona that promotes rapid systemic clearance, a primary challenge in nanomedicine. In this study, we developed a pH- and GSH-sensitive "stealth" nanodelivery system, PTX@NPs-aPD1-IL, for sequential drug release. By using a biocompatible choline-based ionic liquid (IL) as the coating for NPs, the interaction and adsorption of NPs with serum proteins were reduced, achieving targeted delivery to the lung organ and increasing drug accumulation. In the weakly acidic extracellular tumor microenvironment (pH 6.5), the anti-PD-1 antibody (aPD-1) was first released to block the PD-1/PD-L1 pathway and restore the immunocidal function of T cells. In the highly reductive intracellular environment of tumor cells, the disulfide bonds were cleaved, causing NPs to rupture and release paclitaxel (PTX). It induced tumor cell apoptosis and triggered immunogenic cell death (ICD), promoted dendritic cells (DCs) maturation and activated T cells for chemo-immunotherapy. In the mouse orthotopic lung cancer model, PTX@NPs-aPD1-IL exhibited superior efficacy to other treatment groups at the same dose. This was due to the significantly increase in the release of immune factors, including TNF-α and IFN-γ, and the promotion of CD8+ T cells recruitment, which induced a stronger immune response, and thus enhanced the anti-lung cancer effect. In summary, PTX@NPs-aPD1-IL provided a promising strategy for effective chemo-immunotherapy for lung cancer through sequential release profile.