Hydrocolloid Inks for 3D Printing of Porous Hydrogels

A new methodology is presented for generating hydrocolloid inks, emulsions of hydrogel precursor solutions with mineral oil, for solid freeform fabrication of porous hydrogel scaffolds. These hydrocolloid inks exhibit viscoplastic behavior and rapid photopolymerization that permit high fidelity printing of complex geometries. Hydrocolloid inks based on poly(ethylene glycol) diacrylate are utilized to fabricate custom scaffolds using open source 3D printing software and customized paste extruder with cure-on-dispense capabilities. Scaffolds exhibit a hierarchical porosity from the microscale emulsion templated pores to the macroscale lattice structure and geometry programmed into the printing process. The extensibility of this system is also demonstrated by creating hydrocolloid inks from a range of natural hydrogel solutions including cellulose, gelatin, alginate, and hyaluronic acid. Unlike other methods of modulating hydrogel rheology to increase printability, these versatile hydrocolloid inks enable high fidelity printing of hydrogels without relying on high polymer concentrations or complex polymerization mechanisms.