Embryonic stem cells (ESCs) and induced pluripotent stem (iPS) cells have generated tremendous interest in the scientific community because of their unique ability to differentiate or transform themselves into any of the specialized cell types found in the human body. These cells may therefore represent a source material for organ and tissue replacement to treat several debilitating ailments ranging from diabetes to Parkinson’s disease. Unfortunately, the current methods for directing stem cell differentiation are notoriously inefficient and difficult to control. Scientists currently lack the tools to properly obtain the large populations of differentiated cells needed for these future clinical applications. For example, traditional culture practices and tools result in unsynchronized growth and differentiation of stem cells which have been shown to reduce yields of desired cell types. The work proposed in this project will address this problem by adapting engineering tools and methodologies which have been applied, over the past decade, to areas ranging from the automotive industry to microelectronics. Functionally, our proposed tools revolve around a common theme where we rigorously control the size of the initial stem cell colony or, in other strategies, aggregates known as embryoid bodies (EBs) prior to differentiation. One objective of our research is to assess the extent to which size control influences the outcome of lineage specific differentiation and then determine an optimal size range. A second objective is to develop engineering tools that regulate the addition of molecules called induction factors to the culture media that bathes the stem cells. Exposure to combinations of these signaling molecules guides the stem cells toward a preferred lineage. Using microfluidics, we will be able to exquisitely control the concentration and combination of these differentiation inducers and determine whether we can further increase differentiation yields. Altogether, these tools represent an enabling set of technologies that will permit scientists to more closely probe the mechanisms behind stem cell differentiation. This research provides the fundamental basis for a technology that has the potential to produce large populations of differentiated cells that will speed the translation of stem cell technologies for therapeutic and diagnostic applications.
Statement of Benefit to California:
There has been tremendous interest in harnessing the unique capability of pluripotent stem cells to both self renew and to differentiate into all specialized cell types found in the human body. The scientific investigation of cells with these capabilities, such as human embryonic stem cells (hESCs) or induced pluripotent stem (iPS) cells, may eventually lead to revolutionary cell based treatments against several debilitating pathologies that affect many citizens of California such as type I diabetes mellitus, Parkinson's disease, and sickle cell anemia. While there is significant promise for this work, the transition from the laboratory bench toward clinically viable therapies has been slowed by several limitations. In particular, current state-of-the-art methodologies for directing stem cell differentiation toward specific lineages are notoriously inefficient and often result in mixed populations of cells. In order for the state of California to maintain its scientific leadership position in the emerging field of stem cell biology and ultimately drive the deployment of clinically relevant stem cell therapies to its citizens and the world, there is a critical need for new tools and strategies that will improve the efficiency and scalability of stem cell differentiation. The work proposed in this project integrates sophisticated engineering tools of microelectromechanical systems, microfluidics and synthetic materials into devices and systems that will move towards improved differentiation yields. The hypothesis-driven studies described in this proposal enable us to emphasize experimental parameters which are not attainable by traditional culturing practices as the engineering tools provide rigorous control over the microenvironment surrounding the differentiating stem cells. The engineering tools developed in this program form the basis for a technology which is scalable and robust, which will not only benefit the scientific community but will also drive emerging commercial and medical development of stem cell therapeutics and other advances that will the benefit the state of California and its citizens.