Biomedical engineers from the University of Utah are pushing the envelope of 3D bioprinting with a new approach that could enable the printing of ligaments and tendons. The process, which has been in development for two years, was pioneered in collaboration with Carterra, Inc., a Salt Lake City microfluidic device manufacturer for the medical sector.
Treatments for a badly injured ligament, tendon or disc do exist already, but as they often rely on taking tissue from another part of the patient’s body or from a cadaver, it can be a tricky and not always fully effective procedure. Spinal discs especially are difficult to mend or replace, as they are highly complex and integrate bony interfaces throughout their structures.
For two years, the University of Utah team has been working on a solution for these medical challenges using a unique bioprinting approach. The approach consists of stem cells from the patient’s own body fat which are deposited on a layer of hydrogel material to form a tendon or ligament structure. This bioprinted tissue is then grown in vitro before being implanted.
From a more technical perspective, the research team is working with a modified 3D printer provided by Carterra. The machine, originally used to print antibodies for cancer screening applications, has been fitted with a special printhead designed for depositing human cells in an extremely precise way. The precision was crucian because as connective tissues, ligament and tendon tissues are made up complex cellular patterns that shift from tissue to bone cells.
“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,” explained Robby Bowles, the biomedical engineering assistant professor who co-authored the study.“It allows us to very specifically put cells where we want them.”
“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,” added the researcher, who specializes in musculoskeletal projects.
In demonstrating the 3D bioprinting concept, Bowles and his team printed cells that were genetically modified to glow a fluorescent colour. This enabled the team to visualize the pattern of the printed cells on the hydrogel material.
And though the innovative process is being developed specifically for tendons and ligaments, the team says it can be adapted for other types of tissue engineering applications. It could even be used for bioprinting whole organs down the line. Interestingly, the approach can also be adapted to any type of 3D printer.
The research study detailing the bioprinting concept was recently published in the journal Tissue Engineering, Part C: Methods.