Scientists have achieved a remarkable feat by enabling the eyes of mice to perform part of the photosynthesis process using specially designed eye drops derived from spinach leaves.
The experimental treatment, developed by researchers at the National University of Singapore, was created to combat dry eye disease, a condition that affects millions of people around the world. Instead of turning eyes into miniature plants, the treatment uses photosynthesis machinery to generate antioxidant molecules that help reduce inflammation and tissue damage. The findings, published in the journal Cell, suggest that plant-inspired biotechnology could one day offer a new way to treat eye disorders using only ordinary ambient light.
How scientists made mice’s eyes perform Photosynthesis
The research team extracted structures known as thylakoid grana from chloroplasts found in spinach leaves. These structures contain chlorophyll and are responsible for light-dependent photosynthetic reactions in plants.Next, the scientists encapsulated thylakoid grana into microscopic particles, creating a system called the Photoreaction-Enriched Thylakoid Foundry, or LEAF. When administered as eye drops, the system was able to absorb light and trigger reactions similar to the early stages of photosynthesis.
Importantly, the treatment did not allow the mice to produce sugars as plants do. Instead, it produces beneficial molecules that can help protect the eye from damage.
How the trial targeted dry eye disease
Dry eye disease affects the tear film that covers the surface of the eye. The condition can cause discomfort, irritation, blurred vision, and inflammation. In severe cases, this may damage the cornea and affect overall eye health.The researchers focused on the disease because it is closely linked to oxidative stress, a process in which harmful molecules known as reactive oxygen species accumulate and damage tissues.The LEAF system is designed to generate NADPH, a molecule that is naturally produced during photosynthesis. NADPH acts as a powerful antioxidant, helping cells neutralize harmful compounds and reduce inflammation.
What the study found
To test the treatment, the researchers caused mice to develop dry eye disease before using experimental eye drops. After five days, mice treated with LEAF showed better tear production and less corneal damage compared to animals that received only saline.The treatment also reduced signs of inflammation in the eye. According to the researchers, the improvements were similar to those achieved using an existing commercially available drug used to treat dry eye disease.These results suggest that a plant-derived photosynthetic system successfully helped counteract the biological processes that cause this condition.
Borrowing a trick from nature
Although photosynthesis is usually associated with plants, some animal species have developed unusual relationships with photosynthetic organisms.
For example, some marine slugs can retain chloroplasts from the algae they consume and use them for limited photosynthetic activity.Inspired by these natural examples, the researchers explored whether components of photosynthesis could be adapted for use in mammalian tissue. Their goal was not to make animals photosynthesize, but rather to harness beneficial aspects of the process for therapeutic purposes.The success of the experiment demonstrates how biological systems found in nature can inspire innovative medical technologies.
Will the treatment turn the eyes green?
Although they contain photosynthesis machinery originally derived from spinach, eye drops are not expected to change eye color.The researchers explained that the concentration of the substance containing chlorophyll in the solution is very low, which makes the droplets appear transparent. As a result, treated eyes do not become green or show any visible plant-like characteristics.The treatment works at a microscopic biochemical level rather than changing the appearance of the eye.
What will happen next?
This technology is still in its early stages and has only been tested on mice. Before it can be used in humans, researchers must conduct extensive safety evaluations and clinical trials to determine whether the treatment is safe and effective.The team is currently working on future human studies. If these trials prove successful, the treatment may provide a new non-surgical treatment option for dry eye disease based on light-driven biological interactions.Although much work remains, the study offers a glimpse into a future where plant-inspired medicine could help treat common eye conditions in entirely new ways.
