Multifunctional astragalus polysaccharide composited microneedle promotes oral ulcers healing by inhibiting ferroptosis via Nrf2/HO-1/SLC7A11 axis

Oral ulcers, a prevalent mucosal disorder with high recurrence rates, remain challenging to treat due to the oral cavity's dynamic environment and the multifactorial nature of ulcer progression. Here, we report a multifunctional microneedle (MN) patch loaded with astragalus polysaccharide (APS-MN) that integrates rapid mucosal penetration, reactive oxygen species (ROS) scavenging, and ferroptosis inhibition to accelerate ulcer healing. Unlike conventional MN systems reliant on synthetic drugs or prolonged dissolution, APS-MN leverages the natural antioxidant and immunomodulatory properties of APS-a traditional Chinese medicine-derived polysaccharide-enabling complete drug release within 2 min and targeted delivery to ulcer bases. In vitro and in vivo studies demonstrate that APS-MN promotes M2 macrophage polarization, suppresses pro-inflammatory cytokines (TNF-α, IL-1β), and inhibits ferroptosis via the Nrf2/HO-1/SLC7A11 axis, achieving 88.2 % wound closure in rats within 6 days. Notably, this work combined herbal polysaccharides with MN technology for oral ulcer therapy, offering a biocompatible, non-invasive alternative to corticosteroids and antibiotics. The rapid dissolution, dual antioxidant/anti-ferroptotic action, and scalability of APS-MN position it as a transformative platform for managing recurrent oral ulcers and other redox-imbalanced mucosal diseases.