SINGAPORE, May 16, 2026
Researchers at the National University of Singapore have developed a groundbreaking plant-based eye drop technology that enables corneal cells to generate protective molecules using ambient light, offering a potential new treatment for dry eye disease. The innovative therapy, called LEAF (Light-reaction Enriched thylAkoid NADPH-Foundry), uses nanosized photosynthetic structures extracted from spinach plants to restore the eye’s natural antioxidant defenses and reverse corneal damage.
The study, published in the scientific journal Cell on May 15, 2026, demonstrated that the experimental eye drops outperformed existing dry eye treatment Restasis® in preclinical studies, restoring damaged corneal tissue to near-healthy levels within just five days.
Plant Photosynthesis Machinery Used to Heal Human Eyes
The research was led by Associate Professor David Leong Tai Wei from NUS’ Department of Chemical and Biomolecular Engineering. Scientists extracted the thylakoid grana, the photosynthetic membrane structures inside spinach chloroplasts responsible for converting light into biochemical energy, and engineered them into nanosized particles capable of functioning inside mammalian cells.
Once delivered through eye drops, the LEAF particles enter corneal cells and use visible ambient light to generate Nicotinamide Adenine Dinucleotide Phosphate (NADPH), a critical antioxidant molecule that helps neutralize harmful reactive oxygen species (ROS). Excessive ROS production is a major driver of inflammation and tissue damage in dry eye disease.
The team removed the portions of the chloroplasts that consume NADPH while preserving the light-harvesting machinery, effectively creating a miniature biological “NADPH factory.” According to researchers, the engineered particles produced approximately 20% more NADPH compared with unpackaged thylakoid structures.
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Experimental Eye Drops Outperform Existing Therapy
In laboratory tests involving inflamed corneal cells, LEAF rapidly restored NADPH levels within 30 minutes of light exposure while significantly reducing oxidative stress and inflammation. The treatment also shifted immune responses in the cornea from pro-inflammatory to anti-inflammatory states.
When tested in tear samples from patients with dry eye disease, the technology increased NADPH levels nearly 20-fold and reduced hydrogen peroxide, a major damaging oxidant, by more than 95%.
The first preclinical trial, conducted with ophthalmologists from Zhejiang University’s Second Affiliated Hospital Eye Centre, showed that LEAF eye drops administered under normal indoor lighting reversed corneal damage within five days and performed better than Restasis®, one of the most widely used prescription treatments for chronic dry eye disease.
Safety evaluations conducted over two months showed no significant toxicity, irritation, or sensitization effects, supporting the technology’s potential for future human clinical trials.
Future Research to Focus on Clinical Validation
The researchers believe the discovery could represent the first successful example of transplanting functional plant photosynthetic machinery into mammalian tissue to generate therapeutically useful molecules. Dr. Xing Kuoran, first author of the study, described the achievement as a major biological crossover between plant and animal systems.
Beyond dry eye disease, the NUS team sees broader applications for the technology in treating conditions linked to oxidative stress and inflammation, including diseases affecting the retina, skin, and skeletal muscles. Researchers are also exploring strategies to apply photosynthesis-based therapies to internal organs without relying on direct visible light exposure.
The development highlights the growing convergence of synthetic biology, nanotechnology, regenerative medicine, and bioengineering in next-generation therapeutic innovation.
Source: NUS press release
