Imagine cells in our bodies or in lab-grown meat that, like plants, could capture sunlight and produce oxygen. That’s exactly what scientists have just achieved. In a groundbreaking project led by Professor Sachihiro Matsunaga at the University of Tokyo, researchers have successfully developed animal cells that can photosynthesize. This historic achievement could have massive implications for medical science and sustainable meat production.
Why Photosynthesis Matters
Photosynthesis is a process that lets plants, algae, and some bacteria create their own energy by converting sunlight, water, and carbon dioxide into oxygen and sugar. This natural system has never existed in animal cells because these cells do the opposite—they consume oxygen and release carbon dioxide.
By introducing photosynthetic properties into animal cells, Matsunaga’s team hopes these modified cells can become mini oxygen producers, reducing their own oxygen consumption and carbon emissions. Professor Matsunaga described the work as an attempt to create cells that can help support life in a unique way: “All living organisms, including humans, are able to live thanks to photosynthesis,” he said.
Overcoming Decades-Old Challenges
The idea of animal cells with photosynthetic abilities has fascinated scientists since the 1970s. If even part of photosynthesis could happen in animal cells, it could mean using less oxygen, producing less CO₂, and possibly providing cells with their own source of energy. But early attempts ran into serious challenges.
The biggest issue? Animal cells would treat chloroplasts, the cell structures that enable photosynthesis in plants, as foreign invaders. They’d destroy the chloroplasts, much like how they’d fight a virus or bacteria. After years of failed attempts, the idea was eventually abandoned, and it became a widespread belief in science that animal cells could not support chloroplasts.
A New Approach: Letting Cells “Ingest” Chloroplasts
To crack this puzzle, Matsunaga’s team took a fresh approach with two key steps. First, they searched for chloroplasts that could survive the warmer environment of animal cells, which is around 37°C—much higher than typical plant chloroplast temperatures. Finding a chloroplast that could handle the heat was a breakthrough on its own.
Second, they bypassed the immune response by allowing the animal cells to ingest the chloroplasts as though they were food. This natural ingestion pathway helped the chloroplasts avoid being treated as a threat. “Chloroplasts eaten as food could be maintained in the animal cell for at least two days, during which time the initial reaction of photosynthesis could be detected,” Matsunaga explained.
Photosynthesis in Animal Cells: New Energy, Faster Growth
What happened next took the team by surprise. Not only did the animal cells tolerate the chloroplasts, but they also showed an increase in growth rate. This suggested that the chloroplasts provided the cells with additional energy. In the lab, these photosynthetic animal cells were shown to produce oxygen and grow at faster rates than traditional animal cells.
For lab-grown meat production, this could be revolutionary. Currently, one of the biggest obstacles in growing dense tissues for food or medical research is ensuring that cells in tightly packed clusters get enough oxygen. With embedded chloroplasts, cells could produce their own oxygen when exposed to light, enabling them to grow and divide more efficiently.
Medical Potential: Could Photosynthesis Support Human Health?
While human cells with photosynthetic abilities remain a distant goal, Matsunaga’s breakthrough has exciting possibilities in medicine. He suggests that photosynthetic cells could one day be embedded in specific organs, like the heart, to improve oxygen delivery where it’s needed most. For example, placing a small LED near the heart could activate photosynthetic cells, delivering oxygen to the heart muscle in patients with heart disease.
Looking Forward: Next Steps in Photosynthetic Animal Cells
This remarkable discovery has opened the door to exciting new possibilities, but there are still challenges ahead. The chloroplasts currently only function in animal cells for about two days. To make this technology viable in fields like medicine or food production, researchers will need to extend that lifespan. “In the future, we will improve our technique so that chloroplasts can carry out photosynthesis in animal cells for as long as possible,” Matsunaga said.
A Paradigm Shift in Biological Engineering
Professor Matsunaga’s study is a bold step into a future where biology is not only about sustaining life but enhancing it. If we can refine this technology, we might one day see animal cells that produce their own energy, release oxygen, and reduce CO₂ emissions. This breakthrough could change how we tackle food production, medicine, and possibly even climate challenges. For now, Matsunaga and his team’s work is a reminder that in science, limits are often meant to be pushed.