Thermoresponsive antioxidant metal-free carbon nanodot hydrogel: An effective therapeutic approach for ocular surface disease

Abstract

Oxidative stress, an imbalance between the body’s oxidative and antioxidant systems, contributes markedly to the development of numerous ocular surface diseases, particularly dry eye disease (DED). Effective elimination or reduction of reactive oxygen species (ROS) can halt disease progression and alleviate symptoms. This study presents an innovative thermoresponsive, metal-free carbon nanodot (CD) hydrogel, termed F-CD hydrogel, which exhibits potent neutralization capabilities against multiple free radicals, including OH·, O₂⁻·, and ·DPPH. This hydrogel demonstrates remarkable antioxidant, anti-inflammatory, and antiapoptotic capacity, effectively relieving DED symptoms by eliminating ROS at their source. Furthermore, its thermosensitive characteristics enhance the adherence of CDs to the ocular surface. In mouse models of DED, the F-CD hydrogel accelerates epithelial repair, thickens the corneal epithelium, promotes tear secretion, and boosts goblet cell count by up-regulating protective genes while suppressing those promoting apoptosis and oxidative stress. Coupled with its excellent biocompatibility and reduced administration frequency and treatment duration, the F-CD hydrogel emerges as a promising therapeutic approach for DED.