A dual-pronged strategy for bacterial keratitis: ROS-responsive hydrogel eye drops enabling potent deep-tissue antibacterial action and NETs modulation.

Abstract

Effective treatment of bacterial keratitis is constrained by poor ocular drug bioavailability and tissue damage caused by bacterial invasion and the subsequent host inflammatory response. Motivated by molecular insights into the high mobility group box 1 (HMGB1)-driven neutrophil inflammatory amplification loop, a reactive oxygen species (ROS)-responsive poly (vinyl alcohol) (PVA) hydrogel eyedrops (TPG@OC) was developed to integrate deep corneal antibacterial delivery with immune microenvironment modulation. The hydrogel framework was functionalized with glycyrrhizin acid to neutralize extracellular HMGB1, while cornea-penetrating poly (2- (<i>N</i>-oxide-<i>N</i>, <i>N</i>-diethylamino)) ethyl methacrylate (OPDEA) micelles loaded with ciprofloxacin (OC) enable efficient transcytosis-mediated delivery into the deep corneal stroma. In a murine <i>Pseudomonas aeruginosa</i> keratitis model, TPG@OC exhibited prolonged ocular retention, enhanced corneal penetration, and potent antibacterial efficacy, while effectively suppressing ROS accumulation, neutrophil infiltration, extracellular traps formation, and pro-inflammatory cytokine release, thereby interrupting the HMGB1-mediated inflammatory feedback loop. Notably, therapeutic evaluations in a rabbit keratitis model revealed that TPG@OC treatment extended beyond anti-infective efficacy to preserve corneal biomechanical stability, evidenced by relatively regular corneal curvature, alleviated stromal thickening, and substantially reduced deformation under intraocular pressure predicted by finite element analysis. Collectively, this work establishes a dual-pronged hydrogel platform that couples deep antimicrobial delivery with HMGB1-targeted immunoregulation to preserve corneal transparency and biomechanical integrity, offering a promising materials-based strategy for infectious keratitis therapy.