title: Encapsulated arrays of self-assembled microtissues: an alternative to spherical microcapsules.
abstract: 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.
authors.affiliation: Department of Molecular Pharmacology, Physiology, and Biotechnology, Center for Biomedical Engineering, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Adam P
authors.initials: AP
authors.lastname: Rago
authors.forename: Peter R
authors.initials: PR
authors.lastname: Chai
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Morgan
mesh_terms: D000418:Albumins / Q000378:metabolism; D000464:Alginates / Q000494:pharmacology; D002214:Capsules / Q000737:chemistry*; D002470:Cell Survival / Q000187:drug effects; D020723:Glucuronic Acid / Q000494:pharmacology; D056945:Hep G2 Cells; D006603:Hexuronic Acids / Q000494:pharmacology; D006801:Humans; D023822:Tissue Engineering
chemical_list: D000418:Albumins; D000464:Alginates; D002214:Capsules; D006603:Hexuronic Acids; D020723:Glucuronic Acid