Ice-pop making inspired photothermal ultra-swelling microneedles to facilitate loading and intradermal vaccination of tumor antigen

Cancer vaccines hold great promise in the fight against cancer. Here, we report an ice-pop making inspired photothermal ultra-swelling microneedle (PUSMN) patch for facilitating and enhancing cancer vaccination. The PUSMN patch consist of an array of microneedles made from photo-crosslinked methacrylated hyaluronic acid and polydopamine, a near-infrared photothermal conversion material, connected to a customized resin handle like an ice-pop stick. Using a fabrication process similar to ice-pop making, the PUSMNs exhibit a rapid swelling ratio of over 2000 %, enabling straightforward and efficient loading of tumor antigen with just a 1-min incubation in the antigen solution, followed by 15 min of drying. The handle not only ensures convenient application but also guarantees full embedding of the PUSMNs in the skin after penetration. Under near-infrared irradiation, PUSMNs efficiently generate local heat, further promoting the activation and maturation of dendritic cells. In vivo vaccination with the model antigen ovalbumin using PUSMNs combined with near-infrared irradiation elicits robust tumor antigen-specific cellular and humoral immune responses, ultimately resulting in delayed tumor growth. Given its ease of use, efficiency, and safety features, this biocompatible PUSMN patch could greatly improve cancer vaccination.