ELIZABETH LIPKE, Ph.D.
Mary and John H. Sanders Professor
Department of Chemical Engineering
Auburn University
Alabama USA
November 29, 2022
@
4:00 PM
–
5:00 PM
Rapid Production of Engineered Tissue
Microspheroids for Stem Cell Cardiac Differentiation and Maturation
Biomimetic materials offer a novel approach for directing cardiac regeneration, drawing upon the characteristics of developing myocardium to influence the mechanical, structural, and electrical properties of stem cell-derived cardiomyocytes. We have demonstrated that human induced pluripotent stem cells (hiPSCs) can successfully be differentiated into contracting cardiomyocytes within a controlled biomimetic hydrogel microenvironment, achieving developmentally appropriate temporal changes in gene expression, high cardiomyocyte yield, and calcium handling properties similar to age-matched CMs produced using 2D monolayer cardiac differentiation. Furthermore, CMs within our 3D developing human engineered cardiac tissues became progressively anisotropic without external electromechanical stimuli and developed ultrastructural features of mature CMs. To move to scalable, suspension culture-based cardiac tissue production, we built a novel microfluidic platform to rapidly produce cell-laden hydrogel microspheroids; this geometry is optimal for multiple applications, including tissue spheroid-based drug-testing assays, bioreactor-based cell production and injectable therapeutic cell delivery. Hydrogel microspheroids with tightly controlled aspect ratio (spheres and rods) and size can be rapidly produced with high (20 million cells/mL) cell densities, enabling cell encapsulation rates of over 1 million cells per minute. By providing a tunable, biomimetic cellular microenvironment, these hydrogel microspheroids have been shown to support stem cell proliferation and differentiation, including cardiac differentiation of human induced pluripotent stem cells in suspension-based systems. In comparison to aggregate differentiation, we found microsphere differentiation yielded a higher number of cardiomyocytes per initial hiPSC. When varying the microspheroid aspect ratio, cardiomyocytes differentiated in microrods were found to have greater structural maturation as compared those differentiated in microspheres. We have also employed this microsphere production platform for encapsulating cells for use in automated drug testing and large animal therapeutic cell delivery studies.
![]()