How would you like it if you could recharge your batteries just by sitting in the sun? The ability to harness sunlight to convert carbon dioxide (CO2) and water into oxygen and energy has traditionally been the exclusive domain of plants and algae. However, researchers in Japan have now successfully created photosynthetic animal cells.
The biologists took chloroplasts, the cellular components responsible for photosynthesis, from red algae and injected them into hamster cells. As a result, the animal cells gained the ability to photosynthesize light. This achievement, described in detail in a study published on October 31 in the journal Proceedings of the Japan Academy, challenges the assumption that combining chloroplasts with animal cells is impossible.
“To the best of our knowledge, this is the first report of photosynthetic electron transport in chloroplasts implanted in animal cells,” said Sachihiro Matsunaga of the University of Tokyo, who co-authored the paper, in a statement from the University of Tokyo. Photosynthetic electron transport is the stage of photosynthesis that produces energy for a plant or algae.
“We thought that the chloroplasts would be digested by the animal cells within a few hours of being injected,” he added. “However, we found that they continued to function for up to two days, and that there was a transfer of electrons of photosynthetic activity.”
The researchers confirmed this by analyzing chloroplasts in hamster cells using several imaging techniques, and also applied a method that uses pulses of light to establish that photosynthetic electron transport was indeed occurring. “We hypothesized that chloroplasts embedded in animal cells could remain stable and continuously produce energy regardless of environmental conditions,” they write in the study.
While the idea of solar-powered animals is intriguing, it’s not really the goal; the team’s vision for future applications of this technology is more practical. They envision that “planimals,” as they call them, could be incorporated into the engineering of artificial tissues. Laboratory-grown tissues sometimes fail to grow due to a lack of oxygen, and this problem can be solved by introducing photosynthetic animal cells.
“Laboratory-grown tissues, such as artificial organs, artificial meat, and pieces of skin, consist of several layers of cells. However, there is a problem that they cannot increase in size due to hypoxia (low oxygen levels) within the tissue, which prevents cell division,” explains Matsunaga. “By mixing the cells with implanted chloroplasts, oxygen can be supplied to the cells through photosynthesis, with the help of light exposure, thereby improving the conditions inside the tissue, which will promote their growth.”
The researchers noted that the hamster cells with chloroplasts also had a higher growth rate, indicating that the chloroplast provided the animal cells with a source of carbon (fuel) in addition to oxygen.
The team plans to continue their groundbreaking research on these “primitive” cells. Who knows, maybe in the future your houseplants won’t be the only ones to absorb the sun’s rays for nutrition.
