Engineered 3D-Lattice Microneedle Array Patches for Enhanced Nanovaccine Delivery to Dendritic Cells in Cancer Immunotherapy.

Cancer vaccines are designed to activate dendritic cells (DCs), which are potent antigen-presenting cells that initiate antigen-specific adaptive immune responses and inhibit tumor growth. Microneedles (MNs) have emerged as a promising cancer vaccine platform, enabling the noninvasive dermal delivery of cancer antigens and adjuvants to activate dermal DCs. However, conventional solid MNs have a limited surface area, restricting the adsorption of large amounts of bioactive components. Therefore, 3D-printed lattice-structured microarray patches (L-MAPs) with an increased surface area were designed in this study, which permitted the enhanced adsorption of cancer nanovaccines compared to conventional solid microarray patches. L-MAPs were fabricated by using the continuous liquid interface production (CLIP) technology, facilitating the rapid printing of MNs with lattice structures. L-MAPs adsorbed higher amounts of mesoporous-silica-based nanovaccine (MV) on their needle surfaces, exhibiting greater dermal vaccine delivery capacity. Applying MV@MAPs on mouse skin led to efficient DC recruitment, maturation, and subsequent antigen-specific T cell responses in vivo. Consequently, the resulting antitumor immune response considerably suppressed the tumor growth. This approach highlights that using CLIP-printed L-MAPs is a promising strategy for efficient nanovaccine delivery in cancer immunotherapies.