In recent years, updates in 3D printing technologies have allowed medical researchers to print things rarely attempted and impossible for previous generations: Tissues, ligaments, and even tendons.
The innovations, in one case, came from biomedical engineers from the University of Utah. The processes can give patients with badly damaged tendons, ligaments, or ruptured disks faster recovery times or even entirely new implanted tissues.
This process took the Utah team two years to research and development. The engineers took stem cells from a patient's body fat and printed them onto a layer of hydrogel. That hydrogel facilitates cell growth in vitro in a culture, forming either a ligament or tendon in the process. That new tissue is then implanted in the injured or affected area.
Creating an intricate solution for intricate body parts
In previous decades, successfully printing connective tissue has eluded most biomedical engineers. Ligaments and tendons, in particular, have a variety of cells in different patterns because of their proximity to both bone and muscle.
"It will allow patients to receive replacement tissues without additional surgeries and without having to harvest tissue from other sites, which has its own source of problems," said University of Utah biomedical engineering assistant professor Robby Bowles. Bowles co-authored the paper along with former U biomedical engineering master's student, David Ede.
This novel process gives researchers more control over how the ligaments are formed, more than other biomedically developed 3D printed parts.
"This is a technique in a very controlled manner to create a pattern and organizations of cells that you couldn't create with previous technologies," Bowles said of the printing process. "It allows us to very specifically put cells where we want them."
To get that level of control and specificity, the team partnered with a Utah-based company called Carterra, Inc. to customize a solution. Carterra helped the researchers create a special printhead that was attached to a 3D printer normally used to print antibodies used in oncology.
In other cases, scientists printed skin that could work far more effectively than skin grafts. In early 2019, scientists engineered a bioprinter with a distinctive feature — mobility. Ultimately, it was a mobile bedside bioprinter that can heal wounds.
“The unique aspect of this technology is the mobility of the system and the ability to provide on-site management of extensive wounds by scanning and measuring them in order to deposit the cells directly where they are needed to create skin,” said Sean Murphy, PhD, a WFIRM assistant professor who was lead author of the paper.
Problems like the aforementioned aren't just painful injuries; they're hard to treat. Replacement tissues for those needing it are often harvested from elsewhere on a patient's body or from a cadaver. However, cadavers run a higher risk of being rejected by the surrounding tissues or of being poor quality and ineffective.
Addittionally, spinal discs have bony interfaces that have to be recreated to succeed in a transplant situation. And anything 3D printed would have to duplicate the intricate structure of human ligaments.
Today, researchers feel confident their custom printer can reduce the complications involved with a transplant and speed up a patient's healing process.