Engineering news
Designed to create engineered human tissue with blood vessel networks that work like natural ones, the technique was developed at Carnegie Mellon University in Pennsylvania.
Over 100,000 people in the United States currently need organ transplants, the research announcement said. The demand for organs, such as hearts, kidneys and livers, far exceeds the available supply and people sometimes wait years to receive a donated organ. Approximately 6,000 Americans die while waiting each year.
Tissue engineering to create lab-grown organs and tissues aims to close the gap between the availability of organs and the demand for transplants, but creating blood vessel networks that work like natural ones is a major challenge, from tiny capillaries to larger arteries.
The new method, developed by graduate student Feimo Yang, uses 3D ice printing, which generally involves adding a stream of water to a very cold surface.
“What makes our method different from other kinds of 3D printing is that instead of letting the water completely freeze while we’re printing, we let it maintain a liquid phase on top. This continuous process, which is what we call freeform, helps us to get a very smooth structure. We don’t have a layering effect typical with many 3D printing [methods],” Yang said.
The researchers also used heavy water, a form of water with the deuterium isotope of hydrogen. This gave the water a higher freezing point, and helped create a smooth structure.
After the ice templates have printed, they are embedded in GelMA, a gelatin-based material. When exposed to ultraviolet light, the gelatin hardens and the ice melts away, leaving behind realistic blood vessel channels.
The team successfully demonstrated that they could introduce endothelial cells, like those in blood vessels, into the fabricated blood vessels. The cells survived on the gelatin for up to two weeks. The researchers aim to culture the cells for longer in future.
As well as potential use for organ transplants, Yang said that 3D-printed blood vessels could be used for testing the effect of drugs on blood vessels. They could also be coated with a patient’s own cells to see how the cells respond to a drug treatment before it is given to the patient.
“This innovative approach could be a significant step forward in creating complex, lifelike blood vessel networks for use in tissue engineering,” the announcement said.
Yang will present the research at the 68th Biophysical Society Annual Meeting, currently being held in Philadelphia, Pennsylvania.
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