Dual-functional hCe-pHEMA contact lenses for ocular antibiotic release, antioxidant protection, and in vivo corneal bacterial infection treatment

Ocular bacterial infections are typically associated with elevated levels of reactive oxygen species (ROS). Nevertheless, for treating ocular bacterial keratitis (BK), broad-spectrum antibiotics in eye drops or ointments are unable to inhibit ROS and encounter swift clearance and reduced bioavailability. This work developed antibiotic levofloxacin (LEV)-loaded hollow ceria nanoparticles (hCe NPs, ROS scavengers), which were embedded into poly-hydroxyethyl methacrylate (pHEMA) hydrogels to prepare dual-functional contact lenses (LEV@hCe-pHEMA), enabling extended ocular drug delivery and enhanced bioavailability. The integration of LEV@hCe NPs within pHEMA contact lenses preserved good optical transmittance (> 90.0 %), fortified UV-blocking capacities (200–400 nm), achieved controllable LEV release (84.2 % within 120 h), and enhanced ROS scavenging-antioxidative potential (78.4 % within 60 min). In vitro cytotoxicity evaluations revealed low cytotoxicity (cell viability >95.0 %) of the hCe-pHEMA contact lenses and affirmed their good biocompatibility. Notably, LEV@hCe-pHEMA exhibited significant antibacterial efficacy against S. aureus ATCC29213 (89.8 %) and E. coli ATCC25922 (94.2 %), demonstrating their therapeutic potential. In vivo safety evaluations in rabbit models showed no ocular irritation or pathological changes during a 7-day wearing period, confirming the good biocompatibility of the hCe-pHEMA lenses. LEV@hCe-pHEMA contact lenses could be utilized to treat rabbit BK model induced by S. aureus. It could near-completely remove the keratitis (within 7 days), reducing corneal edema and further recovering corneal transparency. The results suggested that LEV@hCe-pHEMA contact lenses could be employed as promising dual-functional smart ocular drug delivery systems for non-invasive ocular therapy.