Basic research using human iPS cells has been carried out with a relatively small number of cells, and a two-dimensional culture method in which cells are grown by adhering them to the bottom surface of a petri dish has been used as a simple and stable culture method. ..On the other hand, in the stage of application to regenerative medicine, which requires a large number of cells, a three-dimensional culture method in which cells are cultured in a suspended state in a medium is considered to be useful in terms of cost.However, in the conventional three-dimensional culture method, human iPS cells form aggregates of non-uniform size, and cell death is likely to occur due to lack of oxygen and nutrients, especially inside large aggregates, and the growth rate decreases as a whole. , There was a problem that the properties of human iPS cells were easily lost.

　This time, the research group cultivated hollow microfibers (human iPS cell fibers) containing human iPS cells, which were produced using cell fiber technology, to sufficiently thin the cell aggregates formed inside. We succeeded in suppressing cell death by maintaining a uniform diameter.Furthermore, by adding an extracellular matrix inside the human iPS cell fiber, we realized the growth with unprecedented high efficiency.In addition, in this culture method, after the cells inside have sufficiently increased, the cells can be taken out, a new human iPS cell fiber can be prepared, and the culture can be restarted. It was found that the high proliferation rate (calculated about 1 billion times per month) and the properties of human iPS cells are maintained over a long period of time.

　This result has the potential to be used as a basic technology for regenerative medicine using human iPS cells, and is expected to contribute to the development and popularization of regenerative medicine.

Paper information:[Scientific Reports] Cell fiber-based three-dimensional culture system for highly efficient expansion of human induced pluripotent stem cells