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Microneedles have shown great advantages in subcutaneous drug delivery and skin disease treatment. Vitiligo is a difficult-tocure skin disease characterized by the depigmentation of the epidermis. Melanosomes produced in melanocytes are transported through dendrites to adjacent keratinocytes, where they accumulate, resulting in skin pigmentation. However, melanocytes in vitiligo patients are functionally disrupted. Silk fibroin (SF) methacrylate hydrogel microneedle can deliver α-MSH to the epidermis directly, where α-MSH helps the protection of melanocytes, extension of melanocytic dendrites, and transfer of melanosomes. In addition, the expression of melanogenesis-related melanocyte-inducing transcription factor and tyrosinaserelated protein 1 (TRP1) was up-regulated, and the number of hair follicle stem cells increased with good proliferative activity. This slow release α-MSH SF-based hydrogel microneedles provides a new idea for the treatment of vitiligo.

Most vaccines are designed to attack tumor cells by activating CD4+/CD8+ αβ T cells. Unfortunately, αβ T cells, which only recognize the peptide antigens in the complexes with polymorphic MHCI/II molecules, surrender to the tumor heterogenicity. As another subset of T cells, γδ T cells become salient in antitumor because of their unique immunotherapeutic roles. Herein, a tumor vaccine is developed with multivalent antigens by fusion of tumor cell membranes with lipids and successfully activated γδ T cells via microneedle inoculation. It is certified that the evoked γδ T cells synchronize with αβ T cells revitalizing tumor‐induced immunotolerance. In turn, the tumors of mice are significantly inhibited and their median survival time is prolonged considerably. Moreover, the nanovaccine inhibits tumor recurrence after resection. The therapeutic effects are corroborated with the results from TCRδ−/− mice as well as cytokine expression in tumor.

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