3D Printing of Gelled and Cross-Linked Cellulose Solutions; an Exploration of Printing Parameters and Gel Behaviour

Abstract

In recent years, 3D printing has enabled the fabrication of complex designs, with low-cost customization and an ever-increasing range of materials. Yet, these abilities have also created an enormous challenge in optimizing a large number of process parameters, especially in the 3D printing of swellable, non-toxic, biocompatible and biodegradable materials, so-called bio-ink materials. In this work, a cellulose gel, made out of aqueous solutions of cellulose, sodium hydroxide and urea, was used to demonstrate the formation of a shear thinning bio-ink material necessary for an extrusion-based 3D printing. After analysing the shear thinning behaviour of the cellulose gel by rheometry a Design of Experiments (DoE) was applied to optimize the 3D bioprinter settings for printing the cellulose gel. The optimum print settings were then used to print a human ear shape, without a need for support material. The results clearly indicate that the found settings allow the printing of more complex parts with high-fidelity. This confirms the capability of the applied method to 3D print a newly developed bio-ink material.

Extrusion-Printing of Multi-Channeled Two-Component Hydrogel Constructs from Gelatinous Peptides and Anhydride-Containing Oligomers

“…Thus, printing resolution diminished, and the continuous structure of the smaller channels was compromised. This problem is not unique to the two-component hydrogels employed in this work, but inherent to printing flexible materials by extrusion [ 42 ]. Solutions to address this problem include an outer support structure that is manually or automatically added during the printing processor printing into a bath supporting the manufactured structure [ 20 , 43 ].…”

Hydrogel Properties and Their Impact on Regenerative Medicine and Tissue Engineering

“…Due to the unique properties of HGs, mainly their ability to incorporate cells and their high viability, HGs have found broad application in bioink production. The most widely used HGs as bioinks include alginates [ 138 , 139 ], gelatine methacrylate [ 140 , 141 , 142 ], cellulose [ 143 , 144 ], and chitosan [ 145 , 146 ]. Additionally, with bioprinting, live tissue can be incorporated into the system, which could not be achieved by standard 3D printing techniques.…”

Complex Geometry Cellulose Hydrogels Using a Direct Casting Method

“…However, cellulose gel has a weak mechanical structure and is very difficult to shape [ 15 ]. To this end, methods such as dry–wet spinning [ 16 ] and sacrificial templating have been used to shape cellulose hydrogel [ 17 , 18 , 19 ]; recently, three-dimensional (3D) printing of cellulose gel using a 3D bioprinter has been used to shape cellulose hydrogel [ 20 ].…”