3D Bioprinting of Cellulose Structures from an Ionic Liquid

Abstract This article reports on 3D bioprinting of dissolved cellulose to produce small feature structures with a tailored design of regenerated cellulose. The process consists of dissolving cellulose with different origins and molecular weight in an ionic liquid (1-ethyl-3-methylimidazolium acetate), controlled multilayered dispensing, and coagulation. The printability was examined by studying the viscosity of cellulose solutions and by varying the settings of the printer setup regarding flow rate and needle dimensions. Water was added as a nonsolvent, enabling a coagulation process to form a gel structure of the printed solutions. By printing on a coagulating gel, the printed solutions were regenerated within a few seconds. Rheology analysis showed that higher concentrations of cellulose and cellulose of a high molecular weight were shear thinning, providing favorable printing properties. Printing 3D structures of cellulose dissolved in an ionic liquid followed by coagulation by a nonsolvent was possible. Both complex patterns of 2D structures as well as multilayered prints were created to obtain 3D structures. This novel method allows for the production of spatially tailored 3D gels or membrane structures made from cellulose.