What do cotton candy and artificial organs have in common? More than you might think.
Leon Bellan, assistant professor of mechanical engineering at Vanderbilt University, is using a cotton candy machine to spin out networks of tiny threads comparable in size, density, and complexity to the patterns formed by capillaries.
“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.”
The goal is to make fiber networks that can be used as templates to produce capillary systems required to create full-scale artificial organs.
Cotton Candy Capillaries
To make cotton candy capillaries, the researchers spin a non-sugar polymer into cotton candy and pour a gel over it that contains human cells. Bellan has figured out a way to dissolve cotton candy on demand, so it doesn’t break apart until the gel sets.
Once he tells it to dissolve, he’s left with a three-dimensional structure that mimics our capillaries.
“Some people in the field think this approach is a little crazy,” said Bellan, “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.”
Using a gelatin is attractive to researchers because of the relatively low cost and the fact that cells love to grow on it. Specifically, the properties in hydrogels can be tuned to closely mimic those of the natural extracellular matrix that surrounds cells in the body.
Now that Bellan and his team have shown that this technique works, they will be fine-tuning it to match the characteristics of the small vessel networks in different types of tissues, and exploring a variety of cell types.
“Our goal is to create a basic ‘toolbox’ that will allow other researchers to use this simple, low-cost approach to create the artificial vasculature needed to sustain artificial livers, kidneys, bone and other organs,” Bellan said.
The methods used in the process are detailed more extensively in the Advanced Healthcare Materials journal.