Dry eye disease (DED) is the most common eye disease in ophthalmic consultation except for refractive errors. Therefore, an exploration of valid and alternative therapeutic interventions is essential to feed the urgent medical need. It has been demonstratedthat oxidative stress causes multiple adverseeffectsin the pathogenesis of DED, thence alleviating oxidative stress is an effective therapeutic strategy for the DED treatment. Herein, we developed a cerium oxide nanozyme combined with branched poly(ethylene imine)-graft-poly(ethylene glycol) (bPEI-g-PEG). Owing to its stable hydrophilic chains on the surface reducing the cytotoxicity and loads of amines groups that be combined with cerium ions through coordination bonds, the modified nanozymes (referred to as CNP@bPEI-g-PEG) are water-soluble and highly biocompatible. Meanwhile, due to its excellent antioxidantactivity, CNP@bPEI-g-PEG nanozymes can mimic the activity of superoxide dismutase (SOD) and catalase (CAT) to scavenge intracellular reactive oxygen species (ROS). Experimental studies firmly demonstrated that the modified nanozymes were auto-regenerativeand more active in scavenging excessive ROS and alleviating oxidative stress by cerium-element valence state recycling, recovering the morphology of corneal, conjunctival epithelium and the number of goblet cells. The advanced combination may offer a superior therapeutic strategy to deal with oxidative stress for effective treatment of DED.

Posterior capsular opacification (PCO) is the most common complication after cataract surgery, which is primarily caused by the proliferation of the residual lens epithelial cells (LECs) in the lens capsule. Previous studies have demonstrated that a drug-eluting intraocular lens (IOL), aimed to in situ eliminate LECs, are an effective and promising way to prevent PCO. However, because of the potential toxicities of the antiproliferative drugs to the adjacent tissues, the safety of such drug-eluting IOLs is still a highly important issue to be solved. In this investigation, a facile photodynamic coating-modified IOL was developed for effective and safer PCO prevention. An annular poly(lactide-co-glycolic acid) (PLGA) coating loaded with photosensitizer chlorin e6 (Ce6) was prepared by a spin-coating technique. The optical property investigations showed that the Ce6@PLGA coating was particularly suitable for the IOL surface modification. The in vitro cell culture investigation showed that Ce6@PLGA coating-modified IOLs effectively eliminated LECs when treated with light illumination, whereas it appeared to have good cytocompatibility without irradiation. The investigation of the cell elimination mechanism showed that the apoptosis of HLECs may be associated with the cytomembrane disruption induced by ROS, which is generated by the photodynamic coating during light illumination. The in vivo implantation experiments confirmed the desired PCO prevention effect, as well as the safety to and biocompatibility with the surrounding tissues. Thus, the facile Ce6@PLGA coating will provide an effective yet safe alternative of IOL surface modification for PCO prevention.

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