Success in Culturing Stem Cells on the Surface of Ionic Liquids: Toward a Significant Increase in the Efficiency of Culturing Cell Resources that Contribute to Regenerative Medicine

A research group led by Mr. Yuji Kamiyama, a doctoral student in the Division of Soft Matter (JSPS Research Fellow DC) at the Graduate School of Life Science of Hokkaido University, Dr. Takeshi Ueki, a visiting associate professor at the Graduate School of Life Science of Hokkaido University, and Dr. Jun Nakanishi, a group leader at National Institute for Materials Science (NIMS), has established a technology to culture human mesenchymal stem cells, widely used in regenerative medicine, on the surface of a liquid known as an “ionic liquid”. The technology is useful for culturing human mesenchymal stem cells, which are widely used in regenerative medicine. It is expected to significantly increase the efficiency of culturing useful cell resources, which have been conventionally carried out on plastic dishes, and at the same time reduce the amount of plastic waste generated during the culturing process. Since ionic liquids do not evaporate, they do not diffuse into the environment. Unlike plastic dishes, which have been disposable, the ionic liquid can be collected after cell culture, washed, and sterilized by heating/drying, making it an important step toward the development of environmentally friendly reusable “liquid” cell culture substrates.

A solid surface such as a plastic dish is generally used for culturing stem cells that can be used for regenerative medicine. In contrast, if cells can be cultured on a liquid surface such as oil, which does not mix with water, the culture efficiency (effective culture surface area per volume) can be greatly increased, which has long been studied. This would not only reduce the ever-increasing amount of plastic waste, but would also lead to technological innovations such as separation and collection of cells by filtration utilizing the characteristics of liquids, and complete automation of the culture process. On the other hand, fluorinated liquids that have been used in research to date are less cytotoxic, but more expensive than plastic dishes, and their low chemical degradability in the natural environment has been highlighted as an “eternal chemical substance” and a “PFAS problem,” as a compensation for the evolution of cell culture technology. The high cost and environmental impact of cell culture technology has been a concern.

In this study, the research team found an ionic liquid that does not mix with water and has extremely low cytotoxicity, and successfully cultured human mesenchymal stem cells on its surface. Ionic liquids are liquids consisting only of positive and negative ions, but their main feature is that they “do not evaporate or boil even though they are liquids. By washing, heating, drying, and sterilizing the liquid used for cell culture, it is possible to reuse it without discarding it.

The results of this research were published online in Advanced Materials on February 26, 2024.


Original Article:  Ionic Liquid Interface as A Cell Scaffold