For night owls, prolonged screen time users, or anyone struggling with eye discomfort, a revolutionary breakthrough in eye care may soon bring relief. A team of researchers, led by Professors Jinhai Huang and Xingtao Zhou from the Eye & ENT Hospital of Fudan University, in collaboration with Professor Wei Tao from Harvard University, has successfully developed a temperature-sensitive antioxidant carbon dot (CDs) hydrogel eye drop—F-CD hydrogel. This innovation, recently published in Science Advances, holds great promise as a new "weapon" in the treatment of ocular surface diseases.
The ocular surface, as the primary tissue interface between the eye and the external environment, is highly vulnerable to disruptions in its stability. Factors such as environmental pollution, excessive use of electronic devices, and unhygienic eye habits significantly increase the risk of impairing this stability. Today, people who work long hours at desks or use their eyes intensively at night often suffer from various ocular surface diseases. Oxidative stress and antioxidant defense play critical roles in the development and progression of many of these conditions.
Take dry eye, a condition characterized by abnormal tear secretion, which affects 8% to 34% of the global population. In patients with dry eye, the hyperosmolar microenvironment of the ocular surface disrupts the oxidative balance in corneal epithelial cells, conjunctival goblet cells, and meibomian gland cells. Excessive reactive oxygen species (ROS) then trigger a cascade of reactions, including cellular dysfunction, inflammasome-mediated inflammation activation, and cell apoptosis, forming a vicious cycle that makes the disease persistent and difficult to cure. Thus, effectively scavenging excess ROS and maintaining long-term oxidative balance on the ocular surface has long been a pressing challenge in treating ocular surface diseases.
The F-CD hydrogel developed by the team addresses this challenge by simultaneously eliminating multiple free radicals, including hydroxyl radicals, superoxide anions, and 1,1-diphenyl-2-picrylhydrazyl. It exhibits excellent antioxidant, anti-inflammatory, anti-apoptotic, and tissue-repairing properties. Moreover, it stabilizes mitochondrial membrane potential to enhance cellular tolerance and regulates gene expression—upregulating protective genes while inhibiting pro-apoptotic and oxidative stress-related genes. These combined effects promote epithelial tissue repair, increase tear secretion, and boost the number of goblet cells.
This temperature-sensitive antioxidant F-CD hydrogel eye drop shows great potential as a powerful and long-lasting antioxidant intervention for ocular surface diseases. Boasting excellent biocompatibility, it extends the retention time of the medication on the ocular surface, allowing it to act like a "scavenger" that clears away ROS—the "invisible bombs" in the eyes—thus fully exerting its anti-oxidative stress and anti-inflammatory effects. Compared to traditional eye drops, F-CD hydrogel eye drops offer advantages such as lower administration frequency and shorter treatment cycles, providing an efficient and feasible new strategy for patients troubled by ocular surface diseases.