An adhesive chitosan microneedle patch incorporating a Sargassum-derived polysaccharide for skin repair

Microneedle patches have emerged as promising tools for wound repair. However, their clinical utility is limited by poor adhesion and insufficient interfacial stability, which often lead to secondary wound separation and inefficient drug delivery. Here, we report a seaweed-derived bioadhesive microneedle patch that integrates robust tissue adhesion with sustained drug release for effective skin regeneration. The hydrogel patch, composed of chitosan and poly(vinylpyrrolidone) (PVP), absorbs wound exudates and forms mechanically stable adhesion on tissue surfaces. As such, it maintains long-term fixation and protects the wound site. The microneedle array, fabricated via electrostatic interactions between seaweed-derived polysaccharides (contained α-D-Glcp-1→, →4,6)-α-D-Glcp-(1→, and →4)-α-D-Glcp-(1 → units, with a molecular weight of 27,476 Da, named SFP) and chitosan, exhibits rigid, sharp conical tips that enable efficient skin penetration while ensuring strong interfacial adhesion through conformal contact and hydrogen bonding. This intimate microneedle-tissue integration facilitates localized, continuous release of the antibacterial polysaccharide at the wound interface, thereby ensuring sustained therapeutic efficacy. Furthermore, in vivo studies demonstrated accelerated wound closure, enhanced collagen deposition, promoted angiogenesis, and reduced inflammation. Together, these findings establish the seaweed-derived microneedle patch as a multifunctional platform that stabilizes the wound interface, enhances therapeutic delivery, and holds broad potential for diverse biomedical applications.