Gellan Gum Fluid Gel System for Controlled‐Delivery of Cytokine‐Licensed MSC‐EVs to Enhance Corneal Repair in Limbal Stem Cell Deficiency

ABSTRACT

Corneal diseases such as limbal stem cell deficiency (LSCD) are major causes of blindness, and effective options for severe injury remain limited. Mesenchymal stromal cell extracellular vesicles (MSC‐EVs) have immunomodulatory and regenerative activity, which can be enhanced by cytokine licensing of MSCs with TGF‐β1 and IFN‐γ. A key barrier is achieving sustained, localized ocular delivery. Here, we combine licensed MSC‐EVs with a gellan gum fluid gel (FG), a biocompatible, shear‐thinning viscoelastic system designed to improve residence time versus conventional eyedrops. Licensed MSC‐EVs were isolated by size‐exclusion chromatography and characterized by morphology, size, and marker expression. FG was produced by shear gelation and assessed for transparency, rheology, EV release, and cytocompatibility. EVs were spherical (102 nm) and expressed CD9, CD63, CD81, and TSG101. FG behaved as solid at rest and flowed under shear. The lead formulation released 18% of loaded EVs over 6 h, significantly outperforming comparator gels ( p < 0.0001), and was non‐toxic to human corneal epithelial cells and keratocytes. Released EVs accelerated closure in an in vitro corneal wound model and reduced epithelial defect and inflammation in a traumatic LSCD model in vivo. Gellan gum FG therefore enables controlled MSC‐EV delivery and shows promise for treating severe corneal disease.