Functionalized Polymeric Microneedles for Transdermal Delivery of Ovalbumin Protein Antigen

Background/Objectives: Microneedles represent an innovative transdermal drug delivery approach, especially for protein antigens. This study aimed to develop a dual-functional, dissolvable microneedle system loaded with β-glucan and fucoidan in a hyaluronic acid matrix to achieve transdermal immunomodulation and reactive oxygen species (ROS) regulation, exploring its potential in inflammatory disease management and antigen delivery. Methods: The microneedles were fabricated using a two-step casting method. Their morphology, mechanical strength, and dissolution kinetics were characterized. In vitro experiments evaluated the ROS-modulating effects on human dermal fibroblasts, while in vivo studies on C57 mice investigated immune activation and lymph node accumulation of ovalbumin antigen. Results: The microneedles exhibited a mechanical strength exceeding 7.45 N/needle and dissolved within 50 s. β-glucan transiently reduced ROS levels at 6 h followed by a rebound, whereas fucoidan sustained ROS suppression after 12 h. In mice, β-glucan-loaded microneedles triggered local immune activation, and fucoidan-incorporated microneedles enhanced ovalbumin accumulation in lymph nodes by 2.1-fold compared to controls. Conclusions: Integrating β-glucan's immunostimulatory and fucoidan's ROS-scavenging/lymphatic-targeting properties within a single microneedle platform offers a promising multifunctional strategy for treating inflammatory diseases and delivering protein antigens.