Yonghui Ding stands looking into a computer monitor n a cramped corner of an engineering lab at the University of Colorado Boulder. He’s jostling the controls of an Xbox controller, but the Post-Doctoral Biomedical Engineer isn’t ignoring his work.
He’s breaking new ground in biomedical 3-dimensional printing.
“What you see here is the 3D printer we developed,” explains Yonghui. "We got every part from eBay. It's cheap."
He and two other grad students spent the last two years "frankensteining" this machine in their lab. This 3D printer is unique.
"We are able to control the stiffness of the 3D structure," Yonghui says.
That’s a big development in the world of biomedical engineering.
"Different tissue or different organs of our human body have different mechanical properties," Yonghui explains. "Research demonstrates that the right mechanical property is important for correct tissue function."
Being able to have different levels of stiffness in one printed structure allows engineers to closer simulate real organs and organ tissue.
"You want to put the artificial artery into your body and have it function well," Yonghui says. "If they don’t have the right mechanical property it won’t function well."
Here’s how their printer works. They develop a digital black and white image of the structure they want to print. That image is projected through thousands of micromirrors which then goes through an ultraviolet light. The UV light heats a bio-compatible liquid which the team developed.
The black portions of the image are washed away. The white harden into layers. The whiter a portion of the image is the stiffer the layers will cure.
"Potentially we are able to print out artificial living tissue with the right mechanical property and function," explains Yonghui.
The team published their findings in the journal Nature Communications October 5, 2018. The next step is to add living cells to their bio-compatible liquid. They hope that within several years they’ll be able to print structures that can be used in and accepted by the human body.