University of Illinois engineers have created a 3D printer that makes detailed structures with sugar. The printer produces a delicate system of thin ribbons made of hardened isomalt, a sugar alcohol used to make throat lozenges, according to Illinois News.
These water-soluble and biodegradable, sweet structures have many applications in biomedical engineering, cancer research and device manufacturing.
“This is a great way to create shapes around which we can pattern soft materials or grow cells and tissue, then the scaffold dissolves away,” said Rohit Bhargava, a professor of bioengineering and director of the Cancer Center at Illinois. “For example, one possible application is to grow tissue or study tumors in the lab. Cell cultures are usually done on flat dishes. That gives us some characteristics of the cells, but it’s not a very dynamic way to look at how a system actually functions in the body. In the body, there are well-defined shapes, and shape and function are very closely related.”
The printer utilizes a free-form isomalt printing, which means as the nozzle moves through space, the melted material immediately hardens and leaves behind a solid structure. They compared it to leaving a drawing hanging in midair.
The researchers found that the sugar alcohol isomalt worked for printing applications and was less susceptible to burning or crystallization. The printer’s design had to encompass the right blend of mechanical detail in order for it to print solid structures. They took into account the temperature, pressure to extrude the shape from the nozzle, diameter of the nozzle and speed.
“After the materials and the mechanics, the third component was computer science,” Gelber said. “You have a design of a thing you want to make; how do you tell the printer to make it? How do you figure out the sequence to print all these intersecting filaments so it doesn’t collapse?”
The team collaborated with Greg Hurst at Wolfram Research in Champaign to create an algorithm that mapped out printing pathways and created scaffolds.
The advantage to using free-form structures was when the sugar dissolved it left behind connected tubes and tunnels, which could potentially be used as blood vessels in transporting nutrients to tissue.
An additional advantage was by making minor changes in the printer parameters, the researchers could control the mechanical properties of the structure.
“For example, we printed a bunny. We could, in principle, change the mechanical properties of the tail of the bunny to be different from the back of the bunny, and yet be different from the ears,” Bhargava said. “This is very important biologically. In layer-by-layer printing, you have the same material and you’re depositing the same amount, so it’s very difficult to adjust the mechanical properties.”
The printer has long-term applications and potential for working with microfluidic devices and uncovering a vast amount of biological research.