Psoriasis is a chronic inflammatory dermatological disorder characterized by immune dysregulation, oxidative stress, and elevated levels of circulating cell-free DNA. Although systemic or topical immunosuppressants remain the cornerstone of psoriasis management, conventional therapeutic strategies are hindered by several limitations, including suboptimal drug delivery efficiency, off-target adverse effects, and poor patient adherence. Recently, microneedle (MN) technology has emerged as a transformative approach for psoriasis treatment and diagnosis, leveraging its unique advantages in targeted drug delivery and minimally invasive biomarker monitoring. This review provides a timely and comprehensive analysis of MN-mediated therapeutic and diagnostic strategies for psoriasis. First, we systematically elucidate the pathophysiological mechanisms underlying psoriasis. Subsequently, we explore the multifaceted applications of MNs in both therapeutic and diagnostic domains: (1) MNs enable the transdermal administration of diverse therapeutic agents, including small-molecule drugs, oligonucleotides, DNA-based therapies, monoclonal antibodies, inactivated viruses, and nanoparticles, offering enhanced precision in psoriasis treatment; (2) MNs facilitate minimally invasive extraction of disease-associated biomarkers from interstitial fluid, enabling real-time assessment of disease onset and progression. Finally, we critically evaluate the current challenges and future directions in this rapidly evolving field. We anticipate that this review will provide valuable insights to guide further advancements in MN-based technologies for optimized psoriasis management.

Tumor hypoxia is the pivotal factor limiting the therapeutic efficacy of photodynamic therapy (PDT), and can be partly improved by either the oxygen economizing or the oxygen supplementation strategies. Nevertheless, the current studies scarcely integrated the merits of both strategies and neglected the bottleneck of poor oxygen infiltration in deep tumors, resulting in PDT resistance. Herein, we developed an oxygen reservoir-irrigated PDT which integrates oxygen supply, oxygen economizing, and oxygen infiltration altogether. Specifically, mitochondria-targeted mesoporous prussian blue nanoparticles (Ce6@TPB) were fabricated to bridge the gap between oxygen economizing and oxygen supplementation by reducing oxygen output while increasing oxygen input. Hyaluronidase-loaded microneedles were further developed to pave the way for deep PDT with increased infusion of oxygen and photosensitizer by degrading dense extracellular matrix. The modulation of tumor oxygenation and permeability during PDT leads to the complete eradication of primary melanoma and strong immunogenic cell death. Its further combination with checkpoint-blockade inhibitor greatly suppressed the proliferation of distal tumors by reprogramming immune microenvironments, as evidenced by the depletion of M2 macrophage, increased infiltration of anti-tumor immune cells, and elevated excretion of immune cytokines. Therefore, such an oxygen reservoir-irrigated PDT potentiates powerful photoimmunotherapy and provides a favorable prospect for tumor treatment.