Precise Bioprinting Enabled with Aspiration Technology

A new method of bioprinting uses aspiration of tiny biologics, such as spheroids, cells, and tissue strands, to precisely place them in 3D patterns to create artificial tissues with natural properties.

"Tissue spheroids have been increasingly used as building blocks for fabrication of tissues, but their precise bioprinting has been a major limitation," said Penn State’s Ibrahim T. Ozbolat, senior author of a paper published in Science Advances today. "In addition, these spheroids have been primarily bioprinted in a scaffold-free manner and could not be applied for fabrication with a scaffold."

Ozbolat and his team used aspiration-assisted bioprinting along with conventional micro-valve printing to create homogeneous tissues and tissues containing a variety of cells. Aspiration-assisted bioprinting uses the power of suction to move tiny microscopic spheroids. Just as one could pick up a pea by placing a drinking straw on it and sucking through the straw, aspiration-assisted bioprinting picks up the tissue spheroid, holds the suction on the spheroid until it is placed in exactly the proper location and then releases it.

"Of course, we have to gently aspirate the spheroids according to their viscoelastic properties so no damage occurs in transferring the spheroids to the gel substrate," said Ozbolat. "The spheroids need to be structurally intact and biologically viable." By controlling the exact placement and type of spheroid, the researchers have been able to create samples of heterocellular tissues, those containing different types of cells.

"We demonstrated for the first time that by controlling the location and distance between spheroids we can mediate collective capillary sprouting," said Ozbolat. The researchers were able to create a matrix of spheroids with capillary sprouting in the desired directions.

The researchers suggest that this method can be cost effective because the equipment required costs under $1,000 and is easy to use. They report that the system "can be useful in a wide variety of applications, including but not limited to organ-on-a-chip devices, drug testing devices, microfluidics, in vitro human disease models, organoid engineering, biofabrication and tissue engineering, biocomputing, and biophysics."