Bioelastomers and Granular Materials for Biofabrication of Organotypic Structures

The function of engineered tissues and organs-on-a-chip, including permeability and contractility, depends on scaffold properties. Scaffolds for these applications must precisely control microscale structure, elasticity (1–500 kPa), mechanical anisotropy, and biocompatibility. While 3D printing complex structures from hydrogels is possible, their low mechanical support (1–10 kPa) often leads to collapse under cellular forces during tissue formation. Polymers, though useful, have limitations: common polyesters like PLGA are too rigid (1–200 MPa) for soft tissues and are non-permeable to proteins and cells. These challenges are particularly relevant for vascularization, where enclosed conduits need to be embedded within a scaffold that maintains cellular structure and mechanical properties, or in the engineering of functional organs like the heart's left ventricle.

In this presentation, I will discuss how extrusion 3D printing of thermoplastic elastomer composites has increased the fabrication efficiency of the Biowire heart-on-a-chip device by over 60,000%. Additionally, I will cover a high-throughput 3D printing method using coaxial extrusion to create perfusable elastomeric microtubes with very small inner diameters (350–550 μm) and wall thicknesses (40–60 μm). This technique enables the production of biomimetic structures resembling cochlea and kidney glomeruli, allowing for efficient, high-throughput generation of perfusable structures suitable for seeding with endothelial cells in biomedical applications. Finally, using capillary microfluidics and UV crosslinking, we have produced monodisperse elastomeric polymer particles that reinforce hydrogel structures in 3D printing, leading to the creation of self-healing, 3D printable granular materials with enhanced permeability