American Scientist

When Katerina Mantzavinou began her PhD in the laboratory of materials scientist Michael Cima at the Massachusetts Institute of Technology, she joined a project working on implants that could constantly deliver an even dose of chemotherapy medications to patients whose advanced cancer had spread to their abdomens. The laboratory group at the time was considering long, stringlike implants.

“We collaborate with surgeons and oncologists who explained that we need to get as much surface area in the belly as possible exposed to the drug, so something like a sheet would be better than a tube,” Mantzavinou said.

She had some past research experience with origami-inspired biomedical engineering design, and started to consider deployable structures. The implant needed to fold up thin enough to be delivered using tools narrower than a centimeter passing through a small incision, but then unfurl in the patient’s body cavity to create the largest surface area possible for medications to reach cancer-affected tissues.

Mantzavinou experimented by folding paper using origami folding patterns, then designed, 3D-printed, and machined several molds with different patterns that she used to cast stretchy polymers containing drugs. She worked with animals and on the lab bench to show that such drug-containing polymers were well tolerated by the body, and effective at administering an even dose of medication over time.

At this stage, the resulting patterned 10-by-10-centimeter implants (above) are proofs of concept: “These prototypes are too thick to fold down and become smaller than a centimeter, which is our goal,” she says. But they showed that the idea could be investigated, and they captured the research group’s attention. Indeed, Mantzavinou took images of her prototypes with fellow graduate student Lina Colucci that were so broadly compelling that they were one of the winners of the MIT Koch Institute’s image awards for 2018. She next plans to make her implants thinner and hopes to test full-sized prototypes in large animals in about a year. “A very interesting problem to solve will be how to get the implant to unfold fully flat,” she says.