In a groundbreaking achievement that redefines biological boundaries, scientists led by Professor Sachihiro Matsunaga of the University of Tokyo have succeeded in creating animal cells capable of photosynthesis, a discovery that could revolutionize medical research and accelerate advances in the production of lab-grown meat.
Every living organism on Earth depends on photosynthesis, a vital process that only occurs in plants, algae and some bacteria. During photosynthesis, these organisms capture sunlight using chlorophyll, a green pigment present in their cells. They then use this energy to convert carbon dioxide from the air and water from the soil into glucose, a type of sugar that is used as food and fuel. Oxygen is produced as a byproduct and released into the atmosphere, providing the oxygen that all animals, including humans, depend on to survive. On the other hand, humans and other animals inhale oxygen, eat and break down sugars, and emit carbon dioxide, a process completely opposite to photosynthesis.

If even some photosynthesis can occur in animal cells, there will be a decrease in oxygen consumption, carbon emissions and sugar consumption. Thus, the idea of ​​causing photosynthesis in animals had been experimented with since the 1970s. However, integrating chloroplasts (special cellular structures where photosynthesis occurs) into animal cells is not an easy task, because animal cells immediately destroy the chloroplasts, considering them a threat. Additionally, even chloroplasts have difficulty maintaining themselves in the environment of an animal cell. Algae and plant species photosynthesize below 30 degrees Celsius, while animal cells are grown at 37 degrees Celsius.
To make this idea a reality, scientists looked for chloroplasts that could function in warmer animal cells. They eventually discovered schyzon, which grows in a volcanic hot spring in Italy at 42 degrees Celsius and has chloroplastic activity at 37 degrees Celsius. They successfully extracted the chloroplasts from the schyzon, but this time, instead of forcibly injecting them into animal cells, the scientists fed the animals chloroplasts as food. Consumed as food, the chloroplasts were able to survive for two days, during which the first photosynthesis reaction was observed for the first time.

It was also observed that chloroplasts also increased the growth rate of animal cells, implying that they provided an alternative source of food for their hosts. Although a breakthrough in biology, the technology is limited to cultured animal cells, which may prove useful for the production of artificial meat and the development of mini organ models for experimental purposes. There is still a long way to go before this discovery can prove beneficial in medical settings, but the chances are not too bad.