Deformation and Break-up of 3D-Printed Soft Elastic Solids

Bioprinting and tissue manufacturing requires the precise placement of cells and extracellular matrix into macroscopic sized structures with microscopic resolution. However, cell-generated stresses within these 3D-printed structures can result in deformations and instabilities that will alter the shape as it matures. Similarly, capillary forces acting at the interface of soft elastic solids can drive deformations over the length-scale of the elasto-capillary length. These interfacial instabilities provide an opportunity to explore the shape-evolution of 3D-printed structural elements, including beams, sheets, and tubes and can be leveraged to develop new design principles for 3D-bioprinting and tissue manufacturing that capture the deformations resulting from cell-generated stresses. Here, we explore the effects of capillary driven deformation on soft elastic beams, using packed granular microgels as our printed ink. By leveraging the highly tunable material properties of these packed microgel systems, we systematically explore the stability of 3D-printed beams across a range of yield stresses and beam diameters. Furthermore, we compare these interfacially-driven instabilities to the deformation of 3D-printed cellular microbeams under cell-generated stresses.