CU Boulder team 3D prints adhesive elastic materials for tissue repair and beyond
A research team from University of Colorado Boulder (CU Boulder) and University of Pennsylvania have pioneered a process for 3D printing hydrogel materials that are at once elastic, adhesive and resilient, which could be used to print internal bandages to repair damaged heart tissue, cartilage patches or needle-free sutures.
Jason Burdick, the senior author of the research paper and a professor of chemical and biological engineering at CU Boulder, said of the work: “Cardiac and cartilage tissues are similar in that they have very limited capacity to repair themselves. When they’re damaged, there is no turning back. By developing new, more resilient materials to enhance that repair process, we can have a big impact on patients.”
Interestingly, the innovative research project, which was recently published in the journal Science, took inspiration from a somewhat unexpected place: worms, whose bodies can come together to turn into a entwined mass with both solid and liquid-like properties. In the science world, this is known as a “worm blob”. This concept was translated by integrating intertwined molecule chains, or entanglements, in the 3D printing material.
The creation of this resilient band-aid-like material is made possible thanks to a specific 3D printing process developed by the research team. This process, known as CLEAR (Continuous-curing after Light Exposure Aided by Redox initiation), actually controls the entanglement of the material molecules as it prints. This is done by using a combination of “light and dark polymerization”. As the researchers write: “This generalizable approach reaches high monomer conversion at room temperature without the need for additional stimuli, such as light or heat after printing, and enables additive manufacturing of highly entangled hydrogels and elastomers that exhibit fourfold- to sevenfold-higher extension energies in comparison to that of traditional DLP.”
This technology, which the researchers have filed a provisional patent for, has not only successfully printed materials that are both more flexible and tougher than parts printed on standard DLP machines, they are also adhesive, which allows them to stick to tissues. Matt Davidson, a research associate in Burdick’s lab, says this capability is a first: “We can now 3D print adhesive materials that are strong enough to mechanically support tissue. We have never been able to do that before.”
The next steps in the research will be to study how these 3D printed materials interact with organic tissues, and the researchers hope that down the line their innovative solution will be used to help treat patients with heart defects, support tissue regeneration through the delivery of drugs directly to organs or cartilage and more.
Applications for this 3D printing process could also be used in other sectors, like R&D and manufacturing. According to the CU Boulder team, other research teams and industrial end users would be interested in the CLEAR process since it does not require additional energy to cure parts. “This is a simple 3D processing method that people could ultimately use in their own academic labs as well as in industry to improve the mechanical properties of materials for a wide variety of applications. It solves a big problem for 3D printing,” explained first author Abhishek Dhand, Burdick Lab researcher and doctoral candidate at the University of Pennsylvania.
