Andrew Hudson, Research Staff, Carnegie Mellon University
Adam Feinberg PhD, Associate Professor, Carnegie Mellon University
3D printing of soft materials with an elastic modulus < 1 MPa, such as hydrogels and collagen, is challenging because they can easily deform during the printing process. To address this, we previously developed a technique known as Freeform Reversible Embedding of Suspended Hydrogels (FRESH), which uses a syringe-based extruder to embed and then gel fluid inks within a sacrificial support bath of gelatin microparticles. The print resolution is largely dictated by the size of the gelatin microparticles into which the ink is embedded. To minimize these defects, we have developed a new coacervation process that decreases the gelatin support particle size from ~60 μm using the originally mechanical blending approach down to ~10 μm. This has enabled biopolymers such as collagen to be 3D printed with an accuracy of 30 μm using syringe needles with internal diameters < 100 μm in comparison to an original accuracy of 120 μm, representing a fourfold increase in print resolution. Increasing the 3D printing resolution of collagen and other biological hydrogels is important for using FRESH as a biofabrication approach to engineer tissues for in vitro disease modeling and future in vivo applications in regenerative medicine.