The development of 3D printing applications in the medical field is progressing at a steady rate. Breakthrough findings are being revealed almost every day.
The latest of such developments is the development of a ‘bio-ink’ for three-dimensional (3D) printed materials. The technology could one day serve as scaffolds for growing human tissues to repair or replace damaged ones in the body.
The term ‘bioink’, encompasses materials that mimic an extracellular matrix to support the adhesion, proliferation, and differentiation of living cells in a 3D environment. Bioinks distinguish themselves from traditional biomaterials such as hydrogels, polymer networks, and foam scaffolds due to their ability to be deposited by a 3D printer into a pre-defined structure.
Researchers at the Rutgers State University of New Jersey in the United States explained that bioengineered tissues show promise in regenerative, precision, and personalized medicine, as well as product development and basic research.
3-dimensional (3D) bioprinting utilizes 3-D printing technology to produce functional miniaturized tissue constructs from biocompatible materials, cells, and supporting components such as cell culture media. It involves the layer-by-layer, accurate deposition of these materials into precise geometries, with the goal being the creation of anatomically correct biological structures. One of such biocompatible materials is hyaluronic acid.
Previous studies focused on the use of hyaluronic acid, a natural molecule that occurs in many tissues throughout the body and possesses properties ideal for creating customized scaffolds. This molecule, however, lacks the necessary durability for tissues.
Instead, the Rutgers engineers used modified versions of hyaluronic acid and polyethene glycol to form a gel that was strengthened via chemical reactions and would serve as a scaffold.
This 3D printing system would print gel scaffolds, or support structures, for growing human tissues. Like traditional printers that rely on four pigments to cover the entire color spectrum, the system would include hyaluronic acid and polyethylene glycol as the basic “ink cartridges” and other cartridges featuring inks with different cells and ligands that serve as binding sites for cells
“Instead of an ink color for an inkjet printer, we want the mixture to have properties that are right for specific cells to multiply, differentiate and remodel the scaffold into the appropriate tissue,” said senior author David Shreiber, a professor who chairs the Department of Biomedical Engineering in the School of Engineering at Rutgers University-New Brunswick. “We focus on the stiffness of the gel and scaffold binding sites that cells can latch onto.”
The functional effects of the tuneable mechanical and bioadhesive ligand properties were confirmed with assays of cell adhesion and morphology.
The researchers envision a system where hyaluronic acid and polyethene glycol serve as the basic “ink cartridges” for 3D printing. The system would also have other ink cartridges featuring different cells and ligands, which serve as binding sites for cells. They theorize this method would print gel scaffolds with the right stiffness, cells, and ligands, based on the type of tissue desired.
“Both the stiffness and the binding sites provide important signals to cells,” lead author Madison Godesky said. “What especially distinguishes our work from previous studies is the potential to control stiffness and ligands independently through combinations of inks.”