Human embryonic stem cells (hESCs) have the potential to differentiate into all the types of cells in our bodies. They therefore represent a highly promising source for replacing cells and tissues in countless diseases and conditions (e.g., Parkinson's disease and diabetes). Many laboratories are working on controlled methods to differentiate hESCs into the cell types of their choice. To date, however, no method has been able to reach a 100 % differentiation efficiency. This issue poses a major roadblock to stem-cell based therapies. Specifically, hESCs that are only partially differentiated or remain non-differentiated (due to the inefficiencies in these methods) have the potential to cause harmful tumors or prevent proper integration of the differentiated cells into the body.
We therefore propose a novel method to eliminate these potentially-harmful cells from the beneficial ones, thus enabling these cells to be used for therapy. The current, conventional methods that are used to purify one type of cell from another – either fluorescent-activated cell sorting (FACS) or magnetic-activated cell sorting (MACS) – suffer from several inadequacies. Cells that are purified using both FACS and MACS undergo direct modification by outside chemicals and reagents and cells that are purified using FACS do not survive. While MACS is gentler on cells than FACS, it still is not efficient enough to remove all of the potentially-harmful cells.
Our device will allow us to efficiently and gently purify out the potentially-harmful cells from a mixed population of both beneficial and harmful cells, without modifying or damaging the cells. Our device will also be easily scalable so that we can rapidly purify enough cells to be used in a clinically-relevant application. Specifically, our device is made up of a microfluidic channel that will be attached to a glass surface that is modified with antibodies. These antibodies identify and bind to receptors that are present on the surface of the potentially-harmful cells and trap those cells in the channel.
While FACS and MACS use a similar method of antibody-recognition of cell-surface receptors, they directly label the cells by attaching the antibodies to the cell, whereas in our method, we do not modify the cells in any way. Also, our device will allow us to screen several different surface receptors in one device by attaching different antibodies in each channel. In summary, our novel microfluidic device will provide a new benchmark for purifying out potentially-harmful cells from beneficial cells (derived from hESCs) thus allowing them to be safely used for therapy.
The proposed research will benefit the state of California and its citizens for a number of reasons, both clinical and economic. The ability to implant hESC-derived cells for clinical therapy without the risk of contamination of teratoma-forming cells is of extreme clinical importance. Our technology—a highly efficient, high-throughput cell depletion device that will remove all the teratoma-forming cells—will eliminate this critical bottleneck that has thwarted the safe and effective implementation of stem-cell therapies. This will lead to a significant advancement in the field of regenerative medicine and lead to the treatment of diseases that have thus far been untreatable.
Aside from the clinical impact, the development of our technology with broad clinical application will likely lead to commercialization. This would generate jobs and spur economic development in the state of California. Furthermore, the development and utilization of our technology would educate and train new interdisciplinary scientists, who will be at the forefront of the Medical Sciences and Engineering, thereby providing a strong technological workforce in California.
Overall, the successful development of our technology will enable the implementation of novel stem-cell therapies, improve human health, spur economic development within the state of California, and contribute to the scientific knowledge and technological resources of the state.