Stimulate-and-retain hydrogel strategy integrating oncolytic virus and oxaliplatin for dual ICD-inducing antitumor...

Immunogenic cell death (ICD) provides a promising strategy for cancer treatment by stimulating anti-tumor immunity. However, single ICD inducers often elicit insufficient damage-associated molecular patterns (DAMPs), and the rapid clearance of these DAMPs at the tumor site further prevents sustained immune stimulation. To address these challenges, we developed a polyphenol-based bioadhesive hydrogel antigen reservoir functionalized with dopamine (DA) and loaded with dual ICD inducers. Specifically, thymidine kinase (tk)-deficient oncolytic vaccinia virus (VV, a type II ICD inducer) was combined with oxaliplatin (OXA, a type I ICD inducer), thereby enhancing direct tumor cytotoxicity and synergistically amplifying ICD through distinct mechanisms to promote robust DAMP release. Subsequently, the released DAMPs were captured and retained by the DA-functionalized hyaluronic acid-Pluronic® F127 hydrogel (HADP), forming an antigen reservoir at the tumor site. This synergistic "stimulate-and-retain" strategy not only augments ICD-mediated DAMP release but also prolongs their local availability to sustain immune stimulation. In murine models, the OXA-HADP@VV facilitated dendritic cell (DC) activation, increased IFN-γ ⁺CD8⁺ T cell infiltration, and reduced regulatory T cells (Tregs), thereby achieving effective tumor suppression and strong anti-recurrence effects. Together, this dual ICD-inducing antigen reservoir provides a versatile platform for improving cancer immunotherapy.