Run Out of Cartilage? USU Researcher Studies Bioprinted Tissue
USU researcher develops 3D bioprinted plugs to repair damaged cartilage and treat osteoarthritis.
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Chartrain uses a 3D bioprinter to create engineered osteochondral tissue at the USU‒4D Bio3 Center for Biotechnology. (Photo courtesy of Dr. Nick Chartrain) |
March 18, 2025 by Vivian Mason
Osteoarthritis, the most common form of arthritis, causes chronic pain for millions of Americans. It occurs when the articular cartilage that cushions the ends of the bones wears down over time. Osteoarthritis is characterized by inflammation, tissue degeneration, and the gradual loss of articular cartilage. Active-duty service members and veterans are disproportionately affected.
Research in three-dimensional (3D) bioprinting tissue is a growing field, with studies focusing on the regeneration of various tissue types, including cardiac, renal, skin, and bone. Dr. Nicholas Chartrain, a research scientist with the Uniformed Services University (USU) Center for Biotechnology (4DBio3), has been developing 3D bioprinted osteochondral plugs to repair damaged or diseased articular cartilage. These cylindrically shaped plugs consist of a lower layer of bone tissue and a thinner upper layer of chondral (cartilage) tissue. The purpose of the 3D bioprinted plug is to replace damaged or diseased osteochondral tissue with healthy and functional engineered tissue.
Understanding 3D Bioprinting
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3D bioprinting is 3D printing, but with cells. (Photo courtesy of Dr. Nick Chartrain) |
In the 3D bioprinters used by Chartrain, a digital file acts as a blueprint for fabricating a three-dimensional object, layer by layer. Bioink is extruded from a small nozzle based on the digital file to form a thin layer. The 3D bioprinter builds one layer on top of another, creating 3D objects. This process creates engineered tissue that mimics natural tissue by incorporating cells, growth factors, and extracellular matrix components. Over time, the cells differentiate, remodel their local microenvironment, and begin to perform the biological functions associated with healthy tissue.
3D bioprinted osteochondral tissue could be a promising treatment for osteoarthritis and joint injuries. Current treatments focus on relieving pain and inflammation, which become less effective as the disease progresses. Surgical interventions have drawbacks, such as the need to source healthy cartilage tissue from deceased donors or the limited lifespans of artificial joints. New therapeutic approaches, like 3D bioprinting and tissue engineering, offer promise for osteochondral tissue regeneration. Scientists are moving closer to using 3D printed tissues to help heal bone and cartilage damaged in sports-related injuries to the knees, ankles, and elbows.
The Challenge of Osteoarthritis
“Osteochondral tissue consists of a thin layer of cartilage and the bone underneath it,” Chartrain said. “A lot of people have joint problems, with arthritis being the main one. Unfortunately, the body is not very good at regenerating cartilage, so these issues persist over a period of years, even decades.” The challenges are exacerbated by increasing rates of joint injury and osteoarthritis among younger people.
“The techniques that we have to address osteoarthritis are not ideal,” Chartrain said. “The best technique that we have is total joint replacement, putting in metal and plastic joints. Now, that can be okay for older people, but younger people will probably outlive those artificial joints. As time goes by, people tend to have more pain, less mobility, and poorer outcomes.”
The goal is to create biological tissue that can replace the degenerated cartilage. “What we’ve been doing is taking stem cells from the bone marrow, mixing them into hydrogels to make a bioink, and then bioprinting the bioinks to form an osteochondral plug,” Chartrain said. “The stem cells then differentiate into cells specific to bone and cartilage tissue.”
Overcoming Obstacles
Chartrain notes that creating osteochondral tissue still presents challenges for translation into clinical practice. One major challenge is finding materials that are as strong as those in the human body, yet printable and biocompatible. Chartrain’s work includes developing and testing new materials for 3D bioprinting, a crucial aspect of bioprinting all types of tissue.
What does Chartrain see as the future of bioprinting, particularly at USU?
Bioprinting capabilities and expertise in tissue engineering at USU have been consistently growing, with work being conducted on various tissue systems, including skin, lung, brain, and meniscal tissue. USU is ideally positioned at the nexus between academia, government, and patient care to enable significant advances in tissue engineering and the translation of novel medical products into clinical practice.
Chartrain has been involved with 3D printing for about 15 years and bioprinting for 11 years, focusing on areas such as materials development, tissue scaffold design, and multimaterial bioprinting. He was recruited by a 3D printing research team in his college engineering department to develop new printable materials. His prior experience with CAD (computer-aided design) in high school made him a good candidate for the team. His passion grew as he realized he could obtain a Ph.D. in materials science and engineering by continuing his research in developing new printable materials, with a focus on bioinks and tissue engineering.
Chartrain has worked at USU for more than four years and enjoys the environment. He finds the collaborative atmosphere and focus on solving medical problems that disproportionately impact service members and veterans very fulfilling. He also enjoys investigating the research being done by other scientists and is motivated to synthesize disconnected concepts into new research ideas. Chartrain enjoys designing experiments that require thinking outside the box and discovering new ways to see and do things.
“I like solving problems using engineering, and I like being creative,” Chartrain said. “Bioprinting is going to take a while, but it has a lot of potential to change the way people live. I think the long-term impacts on society will be enormous.”
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