Continuous Harvest Bioreactor System for Expansion and Differentiation of Human Es and Ips Cells Cultured on Intelligent Biomaterials Grafted with Nanosegments( I )

Millions of people suffer from loss and damage of organs and tissue every year because of accidents,birth defects, and diseases. Stem cells, such as human embryonic stem (ES) cells, and induced pluripotentstem (iPS) cells, are attractive prospects for translational medicine. However, human ES and iPS cellsshould be cultured in specific environmental conditions. Therefore, the expensive and laborious cellculture processes required for human ES and iPS cells obstruct cell therapy in translational medicine. Thisis because stem cell culture is a batch type process and cell culture dishes and microcarriers currently inuse are disposable. We will develop a continuous cell culture system using the same dishes andmicrocarriers for the expansion of human ES and iPS cells, which reduces the cost of stem cell culturedramatically because of downsizing the bioreactor system.We develope biomaterials immobilized with (a) thermoresponsive nanobrush (polyNIPAAm), (b)stem cell binding nanobrush (oligovitronectin) and hydrophilic nanobrush (nanosegment). Human ES andiPS cells can be detached when the temperature of culture medium is decreased to be 4-20 °C.In conventional culture of stem cells, the cell culture dishes and microcarriers are disposable (batchtype culture system). However, we have develope the idea of a partial detachment process of stem cells ona thermoresponsive nanobrush surfaces for a continuous stem cell harvest system. In the cell detachmentprocess, 75-90% of the stem cells (not 100%) are detached from the thermoresponsive nanobrush surfacehaving lower critical solution temperature (LCST)=30 °C, which are achieved by lowering thetemperature to 4-20 °C after the stem cells have expanded in confluence. Then, the stem cells can beharvested in the culture medium (first cycle). The remaining cells on the surface can start to expand on thesame nanobrush surface in a fresh culture medium at 37 °C. Then, this process can be repeated many times.Stem cells can be continuously harvested in each replaced culture medium on the same dishes ormicrocarriers for many cycles due to the partial detachment of stem cells.The current automated culture system of human ES and iPS cells is extremely expensive, i.e.,approximately one million US$. We will develop the prototype of bioreactor systems using cell culturedishes and microcarriers grafted with specific nanosegments in this project, which allow the continuousstem cell harvest system with compact size equipment and simple procedures. The bioreactor system usingcell culture dishes and microcarriers immobilized with specific nanosegments (nanobrush) is expected tobe supplied with one or two order less price compared to the conventional automated stem cell culturesystem.Global market of tissue engineering, cell therapy and transplantation in clinical area is 20,000 millionUS$ in 2015 and is expected to be 32,000 million US$ in 2018. Therefore, automated human ES and iPScell culture system with reasonable price, which will be developed in this project is expected to have greatadvantage in the market of the human ES and iPS cell culture.