Engineers at the University
of Colorado Boulder have developed a way to mimic the complex
geometry of blood vessels using 3D printing. The technique could
help doctors come up with new ways to fight vascular disease
such as hypertension, by creating artificial tissue with soft,
pliable arteries and veins. It uses oxygen to set 3D-printed
models with different degrees of hardness.
"Oxygen is usually a
bad thing in that it causes incomplete curing," said Yonghui
Ding, one of the authors of the study. "Here, we utilize a layer
that allows a fixed rate of oxygen permeation." By tightly
controlling how oxygen is spread during the printing process,
the researchers were able to build objects with the same
geometry, but with different levels of rigidity. The results
were published in the journal Nature.
As part of their experiment, the engineers created a small
Chinese warrior figure, printed so that the outer layers
remained hard while the interior remained soft. They also
printed three versions of a simple structure. a beam supported
by two rods. Depending on how hard or soft the different parts
were designed to be, the structure would either stand firm or
slump.
The printer can
currently work with biomaterials down to a size of 10 microns;
about one-tenth the width of a human hair. Future iterations
will aim to get this down even further.