Solar energy integration in animal cells achieved by Japanese scientists

Japanese researchers have successfully introduced photosynthetic capabilities into animal cells, a feat previously considered impossible. In an innovative study at the University of Tokyo, chloroplasts - the photosynthetic structures found in plant and algal cells - were embedded into hamster cells, allowing these cells to photosynthesize light and generate energy for at least two days. This breakthrough holds potential for advancing artificial tissue engineering, addressing challenges of oxygen deficiency that typically limit tissue growth.

Imagine deriving energy just from sunlight. While animals traditionally lack chloroplasts, the University of Tokyo research team has achieved this unprecedented integration, merging chloroplasts with animal cells for the first time.

"As far as we know, this is the first reported detection of photosynthetic electron transport in chloroplasts implanted in animal cells," stated Professor Sachihiro Matsunaga, who led the research. "We thought that the chloroplasts would be digested by the animal cells within hours after being introduced. However, what we found was that they continued to function for up to two days, and that the electron transport of photosynthetic activity occurred."

Using red algae chloroplasts, the team embedded these photosynthetic units into hamster cells and verified their continued function through advanced imaging techniques, including confocal and electron microscopy. They used pulse amplitude modulation fluorometry to confirm photosynthetic electron transport within the animal cells.

Matsunaga suggested that the development could have significant implications for cellular tissue engineering. "Lab-grown tissues, such as artificial organs, artificial meat, and skin sheets, are made of multiple layers of cells.

However, there is a problem that they cannot increase in size due to hypoxia (low oxygen levels) inside the tissue, which prevents cell division. By mixing in chloroplast-implanted cells, oxygen could be supplied to the cells through photosynthesis, by light irradiation, thereby improving the conditions inside the tissue to enable growth," he explained.

In addition to providing oxygen, chloroplasts within the animal cells increased cell growth rates, indicating that they could also serve as a carbon source. Future studies aim to explore the interactions between host cells and chloroplasts, focusing on substance exchange and byproducts that may benefit animal cell functions.

Matsunaga is optimistic about the potential of these "planimal" cells in advancing sustainable practices. "We expect planimal cells to be game-changing cells, which in the future can help us achieve a 'green transformation' to a more carbon-neutral society. We will continue to develop innovative biotechnologies with the aim of realizing a sustainable society and the reduction of carbon dioxide emissions."

Research Report:Incorporation of photosynthetically active algal chloroplasts in cultured mammalian cells towards photosynthesis in animals