These are human stem cells that grew on the 'fiber-on-fiber' culturing system. (Credit - Kyoto University iCeMS)
Culturing a large number of healthy human stem cells may soon be possible using a matrix composed of gelatin nanofibers on a synthetic polymer microfiber mesh.
The ‘fiber-on-fiber’ (FF) matrix was developed by a group of researchers headed by Ken-ichiro Kamei of
Kyoto University’s Institute for Integrated Cell-Material Sciences (iCeMS). It improves on currently available stem cell culturing methods.
Researchers have been working on 3D culturing systems that would allow human pluripotent stem cells (hPSCs) to grow and interact with their environment in all three dimensions, like they would within the human body, instead of in two dimensions, like they do in a Petri dish.
Pluripotent stem cells have the capability to differentiate into any kind of adult cell and have vast potential for treating diseases, tissue regeneration therapies, and for research uses.
Recently reported 3D culturing systems have drawbacks, and result in low quality and quantities of cultured cells.
Kamei and his colleagues formed gelatin nanofibers on a microfiber sheet made of artificial, biodegradable polyglycolic acid. Then, human embryonic stem cells were seeded onto the matrix in a cell culture medium.
Growth factors and supplements could be easily switched from the culture medium to the cells because of the FF matrix. Additionally, the stem cells bonded well to the matrix, resulting in strong cell growth: after four days of culture, over 95% of the cells grew and developed into colonies.
The process was scaled up by the team. They designed a gas-permeable cell culture bag where a number of cell-loaded, folded FF matrices were placed.
The newly developed system was designed so that minimum alterations were needed to the internal environment, decreasing the amount of stress laid on the cells. This system yielded more number of cells than conventional 2D and 3D culture techniques.
“Our method offers an efficient way to expand hPSCs of high quality within a shorter term,” report the researchers in their study published in the Biomaterials journal. Furthermore, as the use of the FF matrix is not restricted to a specific type of culture vessel, it allows for expansion of production without loss of cell operations. “Additionally, as nanofiber matrices are advantageous for culturing other adherent cells, including hPSC-derived differentiated cells, FF matrix might be applicable to the large-scale production of differentiated functional cells for various applications,” the team concluded.