A new 3D printing technique brings researchers closer to producing customized tiny blood vessels that can help prevent clots, according to a group of South Korean scientists.
“Off the shelf” artificial vessels typically do not include an endothelium – the thin membrane of cells that lines the insides of blood vessels, helping to facilitate blood flow and prevent clots, according to the scientists.
When replacing large veins and arteries, this is not a problem, because “blood flow is high even without endothelium, so there is less chance of clot formation” with artificial grafts, they explained in Bioactive Materials.
Endothelial cell layers are essential for 3D-printed small diameter vessels, such as those that might be used for coronary artery bypass graft (CABG) surgery, or clots will develop, they said.
The researchers employed “a dragging technique” in 3D printing that allowed them to create pores in their small diameter vessels. Between the inner and outer layers of the vessels, they infused a bio-ink containing human endothelial cells.
The endothelial cells spontaneously migrated through the pores, establishing an endothelium that covered more than 97% of the vessels’ inner surface, according to their report.
The endothelium was resistant to clot-inducing platelets, and lab experiments with sutures suggested the artificial vessels would withstand the typical stresses of implantation.
The researchers said they believe their technique might also be useful for printing other tubular tissues such as the esophagus, trachea, and intestine.
But first, they acknowledge, they need to test their small-diameter vessels in animals.
