Go to your local fair and watch a carny spin you a cone of candy floss. You might not know it, but that's how your body is put together: the structure of cotton candy is remarkably similar to the fibrous tissue that knits together our organs and our bones. Now, a team of researchers are showing how a souped-up cotton candy machine could be the key to 3-D printing artificial organs on demand.
In a new article published in the Advanced Healthcare Materials journal, an assistant professor of mechanical engineering at Vanderbilt University named Leon Bellan reports that he was able to create a gelatinous cube of artificial capillaries with a modified cotton candy machine. Not only was the cube of microfluidic channels alive, but he was able to keep it from dying for more than a week, significantly longer than most alternate methods. The technique could open the door to being able to 3-D print working artificial organs.
"Some people in the field think this approach is a little crazy," Bellan told Vanderbilt News. "But now we've shown we can use this simple technique to make microfluidic networks that mimic the three-dimensional capillary system in the human body in a cell-friendly fashion. Generally, it's not that difficult to make two-dimensional networks, but adding the third dimension is much harder; with this approach, we can make our system as three-dimensional as we like."
So why does this work? Essentially, cotton candy machines melt down sugar, squeezing them out through tiny holes in a spinning centrifuge, where they re-solidify in strands. You can think of these strands as capillaries, which are used by our bodies to distribute nutrients through our bones and organs. Scientists have tried to make such capillaries using a technique called electrospinning, but it's slow, inefficient, and low-resolution: the average capillary is about 10 microns wide, while electrospinning results in capillaries 10 times too big. Bellan's technique shrinks artificial capillaries down to three microns at their finest resolution.
"The analogies everyone uses to describe electrospun fibers are that they look like silly string, or Cheese Whiz, or cotton candy," said Bellan. "So I decided to give the cotton candy machine a try. I went to Target and bought a cotton candy machine for about $40. It turned out that it formed threads that were about one tenth the diameter of a human hair—roughly the same size as capillaries—so they could be used to make channel structures in other materials."
More work is still needed before Bellan's technique is ready for prime time, although his stated goal is to create a "basic toolbox" that will allow other researchers to create the "the artificial vasculature needed to sustain artificial livers, kidneys, bone, and other organs." But who knows? In the not too distant future, you might be more likely to see a cotton candy machine at an organ bank or a hospital than at a carnival or circus.
[via Vanderbilt News]