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Thanks to WPI undergrads, this sea turtle has a ‘biomimetic’ flipper

Lola, a highly-endangered Kemp’s ridley sea turtle, was outfitted with prosthetic flipper designed and built by three engineering undergrads at WPI. Rob O’Neal for Worcester Polytechnic Institute/Rob O'Neal for Worcester Polytechnic Institute

WORCESTER — It’s been a turbulent decade-and-a-half since Lola’s tangles with fishing gear and predatory fish. The 2002 and 2003 mishaps in the Gulf of Mexico ruined her right flipper, injured intestines and spine, and cost her ability to survive in the wild. Turtle tough, she held to life.

The 14-year-old Kemp’s ridley — most endangered of sea turtle species — was saved twice by rescuers on Mustang Island, Texas, and shuttled from an animal rehabilitation shelter near Corpus Christi to a series of aquariums in the south. Her home since 2008 has been the landmark Key West Aquarium, where — without a flipper — all she could do was swim erratic loops in her saltwater tank.


“It was kind of sad,’’ said Greg Gerwin, curator of the aquarium. “Sea turtles normally move so gracefully.’’

Now Lola’s fortunes are dramatically on the upstroke thanks to a trio of never-say-never engineering undergraduates at Worcester Polytechnic Institute who used an emergent technology — 3-D printing — to fashion a first-of-its-kind prosthetic flipper for Lola. The “biomimetic’’ flipper, along with other 3-D-generated medical devices for wild animals and pets, is part of a quiet revolution underway in veterinary orthopedics — one that may eventually save injured wild animals now routinely euthanized and help domesticated animals live a better life.

Veterinarians have formed odd-couple teams with 3-D engineers to make a cat’s replacement knee, an artificial horse hoof, a plastic beak for a maimed wild goose, a new shell for a tortoise scorched by wildfire. Lola’s new flipper is the latest leap toward next-generation animal prosthetics.

“The potential is huge,’’ said Douglas Mader, veterinarian for the Key West Aquarium.

Lola in 2002, barely more than a hatchling, after one of two rescues off Mustang Island, Texas.Animal Rehabilitation Keep

Also known as additive manufacturing, 3-D printing harnesses computers to devices similar to home printers to manufacture objects — wrenches, aircraft components, sandals, architectural models, garden implements, medical equipment, musical instruments, toys — by spraying layer upon layer of liquefied material, such as plastics, nylon, glass, ceramics, or metal alloys. By tweaking the computer, each object can be quickly customized in ways that no previous manufacturing process allowed.


Mader helped the WPI students by providing X-rays, measurements of Lola’s stump and good left flipper, and an array of other anatomical data to ensure they were designing for an individual creature, for Lola herself, not a generic sea turtle.

With one good flipper, Lola is lucky. It’s not unusual for sea turtles to lose both front flippers to shark attacks, snarls of fish line, or other perils — unlike land turtles, sea turtles cannot retract their limbs to safety of their shell.

“These turtles, otherwise healthy, have to be euthanized because they can’t swim to the surface to breathe,’’ Gerwin said. “This prototype [flipper] is a big step forward. One reason is it holds promise that it might work with double-amputees. That means saving some very endangered marine creatures.’’

The big dream, of course, would be prosthetics so reliable that “rescued’’ animals, like Lola, could be released to the wild. She is old enough to breed and such qualities are badly needed on the reproductive front; marine biologists say there are only 1,000 Kemp’s ridley females worldwide.

The trio of budding young engineers who teamed to conceive, design, and build a custom flipper for Lola — it was their capstone senior project — are Vivian Liang from Portland, Maine; Samantha Varela from Nashua; and Iok Wong from Quincy. All are age 22 and graduated from WPI last spring to new jobs or higher education.


But Varela and Wong flew to Key West — on their own dime — in September to personally fit the flipper.

“Emotionally it was overwhelming,’’ said Wong, whose part in the project included honing the hydrodynamics of the flipper. “Lola accepted it. She didn’t even try to bite us! It was like she knew we were trying to help.’’

These days Lola is chasing squid-cicles with fresh zeal. Squid, in ice chunks, provides both sport for intensely curious turtles and yummy fare. She stays on steady course. The new flipper is powered by the stump of the original; it works because of a closely calculated hydrodynamic design that imitates biology.

“I’ll always think of Lola as my first patient,’’ said Varela, 22, bound for medical school. “We did a lot of research, we learned a lot about sea turtle biology, we tested our design in a wind tunnel. We wanted to be sure the flipper not only ‘worked,’ but would be safe and comfortable.’’

Liang’s speciality, meanwhile, is biomechanics. “I focused on the aspect of Lola’s muscles and the forces she needed to exert the flipper.’’

She added: “I love turtles. I have a pet turtle back in Maine.’’

The big day came Sept. 6, when the flipper was carefully slipped onto Lola’s waggly right stump and cinched with a complex strap.


Hearts fell when the artificial appendage slipped off after a few seconds. Hearts lifted on the third try, when the prosthetic remained attached for four hours and 50 minutes, by Wong’s count. These days Lola wears the flipper all day; it’s removed at night mainly so she doesn’t swim herself silly.

“This is pretty high-tech for a sea turtle,’’ Mader said. “But it’s made Lola’s life easier. She has so much more control. The flipper is almost identical to a real flipper in terms of density, flexibility, and feel. She seems happier; she takes off like a bullet when it’s strapped on.’’

The device is more than an oddity. Around the world — in the United States, in Europe, in South America — veterinarians, engineers, and even a dentist in Brazil are latching onto 3-D technology as a way to improve and often save the lives of animals.

Last year, a greylag goose was found near Sao Paulo with most of her bill sheared off at the base — a freak maiming that left her unable to eat. A dentist and animal activist, Paolo Miamoto, fashioned a lifelike beak with a 3-D printer. It took two complicated surgeries — the first beak was too heavy — but Victoria the goose is back to browsing the beaches of Ilha Comprida, according to Brazilian press reports.

In North Carolina, a green sea turtle was found with a badly fractured flipper. The solution: Print a splint. Using 3-D technology, a group of veterinarians and engineers designed a honeycomb-like brace that encased the limb for 40 days, allowing the bones to knit.


Augie, as the turtle came to be called, had healed sufficiently by last summer to be freed into the Atlantic.

One collaborator on Augie’s case was Denis Marcellin-Little, a French-born professor of orthopedic surgery at North Carolina State University College of Veterinary Medicine and a pioneer in use of 3-D printing for making advanced prosthetics for animals. Marcellin-Little made international headlines after leading a surgical team that successfully installed a chromium cobalt replacement knee in a tomcat named Cyrano — the first implant of a fully functional knee in a feline.

“We do such things because these are good things in themselves — to help a sea turtle, to make life better for a beloved pet cat,’’ Marcellin-Little said in an interview. “But also we are moving forward a technology in ways that should help society as a whole — help people, help animals. We are gaining precision, gaining critical experience. Big things start small.’’

Nickerson can be reached at nickerson.colin@gmail.com.