Researchers at the University of Colorado Denver have developed a method to 3D print liquid crystal elastomers so that they form complex structures with physical properties that match those of complex biological tissues, such as cartilage. The researchers hope that the technique will help with creating patient-specific implants to replace tissues that have been lost because of injury or disease.
At present, generating replacements for diseased or injured tissue is challenging. Tissues have unique properties, such as flexibility and strength, that are difficult to emulate when using synthetic substances. Tissues involved in interfacing surfaces at moving joints, including cartilage, must be extremely hard wearing, but still soft and flexible enough to allow for movement and cushioning.
Certain structures in the body are very complex, such as the components of the spine, which allow for complex movements and are strong and flexible enough to protect delicate neural tissue. “The spine is full of challenges and it’s a hard problem to solve,” said Chris Yakacki, a researcher involved in the study. “People have tried making synthetic spinal tissue discs and they haven’t done a good job of it.”
The Denver researchers have developed a new method to create tissue-like materials that involves 3D printing liquid crystal elastomers. The material has significant shock-absorbing qualities, which makes it highly suited for dynamic joints or protective structures in the body.
“Everyone’s heard of liquid crystals because you stare at them in your phone display,” said Yakacki. “And you’ve likely heard of liquid crystal polymers because that’s exactly what Kevlar is. Our challenge was to get them into soft polymers, like elastomers, to use them as shock absorbers. That’s when you go down the layers of complexity.”
To create structures with high resolution the researchers used a 3D printing technique called digital light processing. With this technique, the 3D printer deposits a honeycomb-like liquid crystal resin, which can be cured using ultraviolet light and built up into lattice structures. The final product mimics the natural structure of cartilage.
“With 3D printing, and the high resolution we’ve gotten from it, you can match a person’s anatomy exactly,” said Yakacki. “One day, we may be able to grow cells to fix the spine, but for now, we can take a step forward with the next generation of materials. That’s where we’d like to go.”
Study in Advanced Materials: Liquid‐Crystal‐Elastomer‐Based Dissipative Structures by Digital Light Processing 3D Printing