(745a) Tissue Origami

Cellular organization within three-dimensional (3D) scaffolds is difficult for tissue engineering due to the inability to precisely position cells within a scaffold. We propose a simple "Tissue Origami" technique that organizes cells at user-defined horizontal and vertical locations. Cells patterned on a two-dimensional (2D) thin film are strategically folded into 3D scaffolds which aligned the cells. To demonstrate the versatility of this approach, we produced vessels and other highly ordered architectural features by simply changing the cell type and pattern. We fabricated a highly porous, foldable, 100 micron thick poly(lactic-co-glycolic acid) (PLGA) thin film by spin-coating solubilized PLGA in chloroform over a template. After seeding the film with endothelial and smooth muscle cells at mathematically determined locations, we folded the thin film using an origami technique to precisely align the cells into 3D scaffolds comprised of porous multilayer stacks. After co-culturing these cells in close proximity within the scaffold in vitro after 2 weeks, we observed the formation of 3D vessels. Transplantation into severe combined immunodeficient mice confirmed vessel formation with immunohistochemical staining. This tissue origami technique provides a unique 3D patterning system that has the potential to mimic the ordered, architectural features of organs in vivo.