A Responsive DNA Hydrogel Containing Poly‐Aptamers as Dual‐Target Inhibitors for Localized Cancer Immunotherapy

Abstract Immune checkpoint blockade (ICB) is emerging as an efficient strategy for cancer immunotherapy, which highly relies on the controlled loading and release of immune checkpoints inhibitors. Herein, a responsive DNA hydrogel containing polyvalent aptamers as dual‐target inhibitors is reported to achieve ICB for localized cancer immunotherapy. This DNA hydrogel is constructed by two ultralong DNA chains generated via rolling circle amplification (RCA), which contained two polyvalent aptamers (PD‐1 and CTLA‐4 aptamers), and is loaded with inflammatory‐responsive nanoparticles that encapsulated restriction endonuclease. The DNA hydrogel achieved the specific enrichment of T cells. The restriction endonuclease is specifically released by responding to the inflammatory microenvironment, which subsequently cleaved the DNA hydrogel at the cutting sites of DNA chains. The released PD‐1 and CTLA‐4 aptamers executed the biological functions as immune checkpoint inhibitors, successfully blocking immune checkpoints to activate T cells in tumor sites; as a result, the killing efficacy toward tumor cells is significantly enhanced. In a melanoma tumor‐bearing mouse model, the DNA hydrogel activated the immune response in tumor tissues and showed notable therapeutic efficacy for the inhibition of tumor progression (≈65%). This responsive DNA hydrogel is expected to be a promising formulation for immunotherapeutic medicines.