Fabrication of Complex Hydrogel Structures Using Suspended Layer Additive Manufacturing (SLAM)

There have been a number of recently reported approaches for the manufacture of complex 3D printed cell-containing hydrogels. Given the fragility of the parts during manufacturing, the most successful approaches use a supportive particulate gel bed and have enabled the production of complex gel structures previously unattainable using other 3D printing methods. The supporting gel bed provides protection to the fragile printed part during the printing process, preventing the structure from collapsing under its own weight prior to crosslinking. Despite the apparent similarity of the particulate beds, the way the particles are manufactured strongly influences how they interact with one another and the part during fabrication, with implications to the quality of the final product. Recently, the process of suspended layer additive manufacture (SLAM) is demonstrated to create a structure that recapitulated the osteochondral region by printing into an agarose particulate gel. The manufacturing process for this gel (the application of shear during gelation) produced a self-healing gel with rapid recovery of its elastic properties following disruption. Here, the physical characteristics of the supporting fluid-gel matrix used in SLAM are explored, and compared to other particulate gel supporting beds, highlighting its potential for producing complex hydrogel-based parts.