November 3, 2015

Researchers create transplantation model for 3-D printed constructs

Samantha Paulsen, a bioengineering graduate student in Jordan Miller’s lab at Rice University,
holds a plate on which several of 3-D-printed silicone constructs have been mounted.
The constructs, which are each about the size of a small candy gummy bear, have been
injected with red dye to better show the network of small vessels inside. (Photo by Jeff Fitlow)

(November 3, 2015) Rice, Penn researchers create implant with network of blood vessels

Using sugar, silicone and a 3-D printer, a team of bioengineers at Rice University and surgeons at the University of Pennsylvania have created an implant with an intricate network of blood vessels that points toward a future of growing replacement tissues and organs for transplantation.

The research may provide a method to overcome one of the biggest challenges in regenerative medicine: How to deliver oxygen and nutrients to all cells in an artificial organ or tissue implant that takes days or weeks to grow in the lab prior to surgery.

Using an open-source 3-D printer that lays down individual filaments of sugar glass one
layer at a time, the researchers “printed” a lattice of would-be blood vessels.
 (Credit: Rice University)

The new study was performed by a research team led by Jordan Miller, assistant professor of bioengineering at Rice, and Pavan Atluri, assistant professor of surgery at Penn. The study showed that blood flowed normally through test constructs that were surgically connected to native blood vessels. The report was published in the journal Tissue Engineering Part C: Methods.

Researchers at Rice University and the University of Pennsylvania demonstrated that blood
flowed normally through the network of small channels in the silicone construct,
which is about the size of a small candy gummy bear. (Credit: Jordan S. Miller/Rice University)

Miller said one of the hurdles of engineering large artificial tissues, such as livers or kidneys, is keeping the cells inside them alive. Tissue engineers have typically relied on the body’s own ability to grow blood vessels — for example, by implanting engineered tissue scaffolds inside the body and waiting for blood vessels from nearby tissues to spread to the engineered constructs. Miller said that process can take weeks, and cells deep inside the constructs often starve or die from lack of oxygen before they’re reached by the slow-approaching blood vessels.

From left, Jordan Miller, Samantha Paulsen and Anderson Ta
stand with the 3-D printer they used to create the silicone constructs.
(Credit: Jeff Fitlow/Rice University)
“We had a theory that maybe we shouldn’t be waiting,” Miller said. “We wondered if there were a way to implant a 3-D printed construct where we could connect host arteries directly to the construct and get perfusion immediately. In this study, we are taking the first step toward applying an analogy from transplant surgery to 3-D printed constructs we make in the lab.”

journal reference >>