Engineering news
Following testing in rats, researchers in South Korea and colleagues in Hong Kong said the new blood vessels are “fully functional”, outperforming existing engineered tissue.
The biomimetic vessels were fabricated using triple-coaxial 3D printing and bio-inks, which were formulated from smooth muscle cells from a human aorta and endothelial cells from an umbilical vein. The vessels have a dual-layer architecture.
“The artificial blood vessel is an essential tool to save patients suffering from cardiovascular disease,” said author Ge Gao. “There are products in clinical use made from polymers, but they don't have living cells and vascular functions. We wanted to tissue-engineer a living, functional blood vessel graft.”
Previous attempts to build small-diameter blood vessels have been fragile and prone to blockage, the researchers said. They often use a stripped-down version of extracellular material, such as collagen-based bio-inks. In contrast, material from native blood vessels contains collagen plus diverse biomolecules that provide a favourable microenvironment for vascular cell growth and preserves the natural complexity of the blood vessel. The research announcement said this provides enhanced strength and anti-thrombosis functions.
The printed blood vessels were matured in a lab designed to tune the vessel's biological and physical characteristics to precise specifications of wall thickness, cellular alignment, burst pressure, tensile strength and ability to contract, mimicking natural blood vessel function.
The engineered vessels were grafted into six rats as abdominal aortas. Over several weeks, scientists observed the rats’ fibroblasts forming layers of connective tissue on the surface of the implant, integrating it into the existing, living tissue.
The researchers aim to improve the vessels’ strength and are planning long-term evaluation of vascular grafts.
The work was published in Applied Physics Review.
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