Scheme 1.

Schematic illustration of JQ-1@PSNs-R-based photothermal immunotherapy. The smooth silica nanoparticles (SNs-S) were etched by hydrofluoric acid (HF) to obtain rough silica nanoparticles (SNs-R). By oxidative self-polymerization of dopamine hydrochloride (DA·HCl), JQ-1 encapsulated polydopamine layer was coated on SNs-R, and the JQ-1@PSNs-R were obtained. After intratumoral injection of JQ-1@PSNs-R and laser irradiation, the photothermal therapy (PTT) kills most tumor cells and triggers the release of tumor antigens. Due to the adhesive properties of polydopamine, the released tumor antigens adhere to the surface of nanoparticles, which promotes the uptake of antigens by dendritic cells (DCs). The DCs migrate to nearby lymph nodes and activate cytotoxic lymphocytes (CTLs). Meanwhile, the JQ-1@PSNs-R effectively downregulate the PD-L1 expression and relieve immunosuppression at the tumor site. Finally, the activated CTLs migrate to tumor sites and eliminate residual tumor cells.