Scientists from the University of Toronto have utilized parts purchased from Ebay to build a 3D printer that is capable of printing rudimentary blood vessels.
All the parts are worth a total of $500
The key to printing organic material like this turns out to be oxygen exposure. By exposing different portions of the printed polymer tissue to oxygen they create different degrees of hardness that resemble real biological tissue
“Oxygen is usually a bad thing in that it causes incomplete curing,” said Yonghui Ding, a Postdoctoral researcher in Mechanical Engineering and the lead author of the study. “We utilize a layer that allows a fixed rate of oxygen permeation.”
“By keeping tight control over oxygen migration and its subsequent light exposure, the researchers have the freedom to control which areas of an object are solidified to be harder or softer—all while keeping the overall geometry the same.”
Just as real blood vessels create an interconnected highway of veins and arteries the researcher decided to begin by creating something that roughly imitates this kind of linear blood transportation system. They printed three different versions of what could potentially resemble two veins connected to a larger artery. This took the form of a simple beam supported by two rods 3D printed to be more or less soft then the other rod-beam structures. All other features like size and shape were identical. As you would expect – harder rods supported the beams and maintained their characteristic shape while the softer rods resulted in partial or full collapse of the structure.
In order to more accurately represent the complexity of a biological organism researchers also decided to print a Chinese warrior figure with a soft polymer interior and harder exterior. For example in the case of most mammals, the skin or hair is more tear resistant while the internal organs are more sensitive and flexible. Again they Accomplished all of this through modulating the polymers exposure to oxygen. As far as other materials are concerned the project was comparatively cheap and simple to conduct.
3D printing elements of the circulatory system are one of the most important preliminary steps to the development of 3D printed organs. Without blood vessels to circulate bio-chemicals around the body everything that makes an organ what it is will not exist. Their inexpensive 3D printer is capable of working down to a resolution of 10 microns which unfortunately is not quite enough to handle the subtleties of biochemical interaction. Nonetheless it marks quite a serious step in the right direction.
“The challenge is to create an even finer scale for the chemical reactions,” said Yin. “But we see tremendous opportunity ahead for this technology and the potential for artificial tissue fabrication.”