Injectable and Degradable\nZwitterionic Cryogels as\nCancer Vaccine Platforms to Prevent Cancer Recurrence after Surgery

Cancer has become a highly prevalent disease and poses\nserious\nthreats to human health. Conventional cancer treatments still face\nhigh risks of recurrence. Training the immune system to recognize\nand eliminate tumors via external stimulation, such as vaccines, emerges\nas a promising approach for cancer prevention and treatment. However,\ninjectable vaccines may have limited immune activation, causing difficulties\nin maintaining long-term immune surveillance of tumorigenesis by tumor-specific\ncytotoxic T cells. Here, degradable zwitterionic cryogels were prepared\nusing the cryogelation technique. The cryogenic preparation maintained\nthe biological activities of tumor antigens and immune adjuvants loaded\nin the cryogels. The macroporous structure endowed the injectability\nof cryogels into the body via conventional syringes. In the presence\nof proteases, the cryogels degraded, allowing sustained release of\nantigens and adjuvants, ensuring continued dendritic cell (DC) recruitment\nand antigen presentation to maturing tumor-specific cytotoxic T cells. <i>In vivo</i> experiments demonstrated that the cryogel cancer\nvaccines elicited robust immune activation and effectively modulated\ntumor microenvironments. The combination with photothermal therapy\nsignificantly inhibited tumor growth, showing great potential for\npreventing postoperative recurrence. Additionally, the zwitterionic\ncryogels were biocompatible without obvious toxicities during degradation.\nThe cryogels could serve as effective vaccine platforms to prevent\ncancer recurrence after surgery.