Bioactive thermoresponsive fibronectin-Pluronic F127 hydrogel for sustained ocular delivery with corneal regeneration...

Corneal epithelial defects resulting from trauma or limbal stem cell dysfunction remain difficult to manage because inflammation, tear dilution, and rapid drug elimination restrict the bioavailability of topical therapeutics. To address these limitations, we developed a thermoresponsive fibronectin-Pluronic F127 (FN-F127) hydrogel eye drop that remains a low-viscosity solution at 4 °C and rapidly transitions into a transparent in situ gel at ocular temperature (37 °C), enabling prolonged surface retention. In vitro, 10 % FN-F127 significantly enhanced human corneal epithelial cell proliferation, migration (>60 % increase in wound-closure rate), and expression of stemness- and junction-related genes (TP63, ABCG2, CDH1, TJP1) compared with controls. In a rat corneal epithelial debridement model, FN-F127 reduced the fluorescein-positive defect area by 83.9 ± 5.3 % at 24 h and 95.1 ± 1.8 % at 32 h, outperforming both control and F127 groups, and achieving healing comparable to free FN despite requiring only half the dosing frequency (twice-daily vs. four-times-daily). Histological analysis showed improved epithelial stratification and stromal organization, while RT-qPCR and immunohistochemistry confirmed significant suppression of inflammatory mediators (IL6, NOS2, TNF-α, NLRP3, IL17) compared to NC and F127 groups. Although F127-based gelation prolongs surface residence, direct FN-retention measurements were not performed and remain a focus for future investigation. Together, these findings demonstrate that FN-F127 provides a thermoresponsive, regenerative, and anti-inflammatory platform that enhances corneal surface repair while reducing dosing burden.