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Seminar Series 2018 – Elizabeth A. Lipke, Ph.D.
November 26, 2018 @ 4:05 pm - 5:00 pm
Elizabeth A. Lipke, Ph.D.
Mary and John H. Sanders Associate Professor
Department of Chemical Engineering
“Rapid Production of Engineered Tissue Microspheres for Regenerative Medicine and Disease Modeling Applications”
Dr. Lipke’s research group employs biomimetic materials to guide induced pluripotent stem cell differentiation and maturation, particularly for the scalable production of human heart tissue, to support therapeutic cell delivery, and to create engineered cancer tissues that recapitulate aspects of the tumor microenvironment for use in drug testing. Most recently, we have established a rapid and readily replicable approach to encapsulate cells in poly(ethylene glycol)-fibrinogen (PEG-Fb) microspheres for a range of applications, including stem cell differentiation, cancer tissue engineering, tissue spheroid based drug-testing assays, and injectable therapeutic cell delivery. Using a microfluidic approach, hydrogel microspheres with uniform shape and size can be produced with high (20 million cells/mL) cell densities. To form the microspheres, aqueous PEG-Fb polymer precursor with suspended cells is infused through the upper inlet of a custom microfluidic device and the mineral oil carrier infused through the bottom inlet; microspheres form at the junction and traverse the outlet channel, where they are photocrosslinked in > 1 second and collected. A range of cell types, including stem and progenitor cells and cancer cells, have been encapsulated with high maintenance of cell viability. By providing a tunable, biomimetic cellular microenvironment, these hydrogel microspheres have been shown to support stem cell proliferation and differentiation, including cardiac differentiation of human induced pluripotent stem cells. The established hydrogel microsphere system also can be employed for encapsulation and delivery of therapeutic cell types; fabricated microspheres supported maintenance of encapsulated endothelial progenitor cell phenotype and outgrowth in vitro and in vivo delivery through injection. Encapsulated cancer cells also remodeled the PEG-Fb and formed dense tissues over time; engineered tumor spheroids were more uniform than spontaneously aggregated cancer cells and could be maintained for multiple weeks in culture for use in drug testing. Overall, rapid and reproducible cell encapsulation in hydrogel microspheres has advantages for use in regenerative medicine and disease modeling applications.
Dr. Elizabeth Lipke is the Mary and John H. Sanders Associate Professor in the Department of Chemical Engineering at Auburn University. Dr. Lipke completed her graduate studies at Rice University followed by a postdoctoral fellowship at Johns Hopkins University. Dr. Lipke’s research focuses on the use of cell-material interactions to create cellular microenvironments that guide tissue formation and direct cellular function. To better understand congenital heart defect formation and advance cardiac regeneration, Dr. Lipke’s research group employs biomimetic materials to direct pluripotent stem cell differentiation and create 3D developing human engineered cardiac tissues; this platform for ontomimetic differentiation has been recently shown to also support in vitro cardiac tissue maturation, including t-tubule formation. To support cells in vivo, Dr. Lipke’s research group has established a platform for fabricating injectable, cell-laden hydrogel microspheres and demonstrated successful microsphere-based delivery of autologous endothelial progenitor cells in an equine wound healing model. Dr. Lipke’s group is also investigating novel peptide ligands for capture of endothelial progenitor cells under physiological shear stress. For cancer research projects, the Lipke lab has created spheroidal and microfluidic chip-based tissue-engineered tumor models that recapitulate key native tumor characteristics for improved drug testing. In recognition of her research, Dr. Lipke has received several national awards including a National Science Foundation CAREER award, a 3M Nontenured Faculty Award, and an American Heart Association Scientist Development Grant. Dr. Lipke was recently invited to participate in the National Academy of Engineering Frontiers of Engineering Symposium. In addition to the recognition of her research accomplishments, Dr. Lipke has received awards for teaching and mentoring of undergraduate and graduate students.