Encapsulated arrays of self-assembled microtissues: an alternative to spherical microcapsules

Rago AP, Chai PR, Morgan JR.
Department of Molecular Pharmacology, Physiology, and Biotechnology, Center for Biomedical Engineering, Brown University, Providence, Rhode Island 02912, USA.

Micro-encapsulation and immuno-isolation of allogenic and xenogenic tissues and cells is a promising method for the treatment of a variety of metabolic disorders. Many years have been spent optimizing spherical microcapsules, yet micro-encapsulation has not achieved its full clinical potential. As an alternative to spherical microcapsules, this study presents an alginate-encapsulated array of self-assembled three-dimensional (3D) microtissues. Monodispersed HepG2 cells were seeded onto a micro-molded agarose gel. Cells settled to the bottom of the mold recesses and self-assembled 3D microtissues (n = 822) within 24 h. This array of densely packed microtissues was encapsulated in situ using alginate. When separated from the agarose micro-mold, the encapsulated array had HepG2 microtissues in close proximity to its surface. This surface could be further modified by a simple dipping process. Microtissue size, viability, and albumin secretion were all controllable by the number of cells seeded onto the original agarose micro-mold, and microtissue shape and spacing were controllable by the design of the micro-mold. This approach to encapsulation and the use of self-assembled/self-packing 3D microtissues offers new design possibilities that may help to address certain limitations of conventional microcapsules.

3D Petri Dishes™ used in this paper (please click catalog numbers for detailed product descriptions):
Catalog # 12-256, and 24-96 are the MicroTissues, Inc products that grow small spheroids. Catalog # 12-81 and 24-35 are used to grow larger spheroids.

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