Microneedle patch technologies in virology: bridging immunization, antiviral therapy, and point-of-care diagnostics.

Microneedle patches (MNPs) represent a transformative transdermal delivery platform capable of painlessly penetrating the superficial layers of the skin to enable efficient delivery of vaccines, antiviral therapeutics, genetic payloads, and diagnostic agents. By directly targeting the epidermal and dermal compartments, which are densely populated with antigen-presenting cells, microneedle (MN)-based delivery can enhance immune activation while reducing antigen dose requirements and improving patient acceptability. These attributes are particularly relevant in virology, where rapid, scalable, and user-friendly delivery systems are essential for routine immunization programs, outbreak response, and pandemic preparedness. Recent advances have expanded MN applications beyond vaccination to include controlled antiviral drug delivery, transdermal administration of nucleic acid-based platforms, and minimally invasive viral diagnostics through interstitial fluid sampling. The solid-state stability of many MN formulations further offers the potential to reduce cold-chain dependence, addressing a major logistical barrier in global vaccine distribution. This review critically examines the design principles, immunological rationale, and virology-specific applications of MNP technologies, spanning preventive, therapeutic, and diagnostic domains. Current translational challenges-including manufacturing scalability, regulatory classification, dose precision, and user variability-are also discussed to provide a balanced assessment of the clinical readiness and future potential of MNPs in virology.