Thermosensitive Polypeptide Hydrogel Encapsulating Doxorubicin-Loaded Hollow Mesoporous Silica and CpG Nanocomplex for Chemo-Immunotherapy

Chemo-immunotherapy has been an emerging synergistic strategy for melanoma treatment. However, major challenges still remain, including side effects of chemotherapeutic agents and insufficient efficacy of immunotherapy. In the present work, we designed a thermosensitive polypeptide hydrogel-based drug delivery system to achieve the codelivery of doxorubicin (DOX) and a Toll-like receptor (TLR)-9 agonist, CpG. The hydrogel system was engineered by incorporating cancer cell membrane enveloped hollow mesoporous silica loaded with DOX and the mPEG-ss-PEI/CpG nanocomplex, resulting in an enhanced therapeutic effect. Drug-loaded hydrogel system exhibited sustained drug release, enhanced immune cell activation, and induction of immunogenic cell death (ICD) of tumor cells. In vivo antitumor studies revealed that the drug-loaded hydrogel effectively inhibited tumor growth, and promoted expansion of CD8⁺ T cells and maturation of dendritic cells (DCs), facilitating favorable modulation of the tumor microenvironment. Hence, the developed drug-loaded hydrogel system has considerable potential as a platform for combinatorial chemo-immunotherapy in melanoma treatment.