(704e) Regulate Embryonic Stem Cell Fates Using Microscale Bioactive Elastic Hydrogel

Embryonic stem cells and induced pluripotent stem cells have great potential to treat and understand diseases. One of the major challenges in stem cell research is how to maintain these stem cells in an undifferentiated state during expansion and how to effectively differentiate them into a specific lineage. Embryonic stem cell maintenance and differentiation are governed by the unique local 3-D microenvironment, which is composed of soluble factors, elastic extracellular matrices (ECM) and neighboring cells. Cells and tissues in the body are organized into 3-D architectures with nanoscale interactions. We have developed a microscale hydrogel system to mimic the 3-D microenvironment. Hydrogels can be tuned to resemble the elasticity and shape of a specific tissue type where soluble factors controlled release to support stem cell development. Mouse embryonic stem cells were used as a model system to demonstrate how tunable microenvironments affect stem cell maintenance and differentiation. Our results demonstrate that a gel-like microenvironment facilitates stem cell maintenance and a liquid-like microenvironment promotes embryoid body formation. Leukemia inhibitory factor (LIF) and retinoic acid (RA) are encapsulated in the hydrogel to achieve controlled release into embryonic stem cell cultures, respectively. The maintenance and differentiation of stem cells are confirmed by cell morphology and immunocytochemistry of specific cell markers. The combination of controlled release and 3-D hydrogels with tunable elasticity will provide a valuable platform for understanding microenvironment-stem cell interactions and efficiently differentiating embryonic stem cells.