One of the ways of making bioengineered tissues is to embed living cells within 3D printed constructs. This is already a common practice in labs around the world, but researchers at North Carolina State University have figured out a way of improving the technique.
One limitation of simply dumping cells into a 3D printed structure is that their orientation ends up random. It’s usually best for cells to line up in a certain direction, as that optimizes the strength, flexibility, and other characteristics of the resulting tissues.
The North Carolina State team are now using ultrasound to align living cells within structures as they’re being printed. “We’ve reached the point where we are able to create medical products, such as knee implants, by printing living cells,” said Rohan Shirwaiker, one of the lead researchers at North Carolina State. “But one challenge has been organizing the cells that are being printed, so that the engineered tissue more closely mimics natural tissues.” It is believed that the new approach will lead to the creation of bioengineered tissues such as the meniscus of the knee, which doesn’t heal on its own and is the cause of much suffering and disability around the world.
The technique relies on a special chamber within which the 3D printing process takes place. The chamber generates ultrasound waves that flow from one wall toward the opposite, bouncing back and creating standing waves. The standing waves motivate the cells to align along with them, and as a structure is printed and cells positioned within, they can be made to take any orientation desired.
“We were able to control the alignment of the cells as they were printed, layer by layer, throughout the tissue,” said Shirwaiker. “We’ve also shown the ability to align cells in ways that are particularly important for other orthopedic soft tissues, such as ligaments and tendons.”
Study in journal Biofabrication: Ultrasound-assisted biofabrication and bioprinting of preferentially aligned three-dimensional cellular constructs…