How hedgehogs might make American football safer

Cleveland, Ohio —The quills of a hedgehog, which cushion the mammal from harm when it falls from trees, inspired researchers to create a product that could one day prevent football concussions, cushion the inner soles of running shoes and protect soldiers.

Hedgemon recently received patent approval for its hedgehog-inspired impact protection technology.

The initial focus is to create a liner for football helmets to protect players from concussions, CEO Emily Kennedy said. The company plans to seek venture funding and supply or license its technology following a test this fall at a certified lab.

"We've had some preliminary conversations with all football helmet manufacturers," Kennedy said. "We need the data to blow their socks off."

It has been more than five years since Kennedy and others in the University of Akron's graduate degree program in biomimicry began discussing how to prevent concussions, a frequent injury among football players of all ages. In recent years, there has been increasing concern that concussions cause long-term brain injuries.

Biomimicry involves copying nature to solve human problems, so Kennedy and classmates, including Bill Hsiung, began investigating which animals had qualities to absorb impacts to the head and body.

They studied woodpeckers and bighorn sheep, but realised the bird's beaks and sheep's horns absorb only linear impacts, caused by direct blows to the head that knock the brain against the inside of the skull. They aren't affected by angular impacts, caused by indirect or glancing blows that spin the brain against the inside of the skull, she said.

Research has shown angular impacts are more damaging to the brain than linear impacts, but no football helmet can absorb rotational energy, Kennedy added.

They then discovered the hedgehog.

"We were surprised by that connection to the hedgehog, but in their behaviour in the wild they fall pretty regularly," she noted.

Hedgehogs – which are small, each weighing only about 1.5 pounds – escape predators by curling into a tight ball and falling from trees. Their 7,000 quills, which are arranged in overlapping layers, act as a shock absorber, so the animals are uninjured after they hit the ground.

From nature to prototype

To create a prototype, they obtained several pelts from hedgehogs that had died naturally and observed two hedgehogs living at the time at the Cleveland Metroparks Zoo.

Hedgehog quills are mostly hollow and although they are light, they are very strong.

Using a 3D printer, the team created impact protection modules – squares of overlapping and pitched flexible polymer "quills," modelled after the pattern of quills on hedgehogs. After numerous experiments to create the best pattern and flexibility, including dropping modules from high points, more than a dozen were inserted into a helmet liner, also created by a 3D printer.

Last October, the liner was inserted in a clear helmet and tested at ICS Laboratories in Brunswick. The lab is one of five in the country approved for third-party validation testing by the National Operating Committee on Standards for Athletic Equipment, which certifies athletic equipment, including helmets.

The Hedgemon helmet was put on a head form full of oil, which was subjected to linear and angular impacts at several velocities, Kennedy said. Their helmet was tested against other brand-name helmets.

"We found, in some areas, we outperformed other helmets, and in others we were not quite there yet," she said. "For the first full-scale, 3D-printed liner, we were feeling pretty good."

The team is making improvements to the modules and the liner, including adding more modules and making the liner more durable. They plan to use injection-moulded parts for the modules and liner for the test this fall.

Just getting started

Hedgemon received $50,000 (€44,500) in startup funding from the University of Akron Research Foundation's Spark Fund. After completion of the Spark Fund project, which included the helmet testing, the foundation licensed the technology to Hedgemon, which is now in a coworking space at StartMart in tower city centre in Cleveland.

As the company evolves, its team members hold other jobs. Kennedy is director of external relations for UA's Biomimicry Research and Innovation Center. Hsiung is a postdoctoral fellow at the University of California, San Diego; and Swift is a design engineer at Moog Flo-Tork, a space and defence group firm in Orrville. Paige is at the Cleveland Institute of Art.

To date, Hedgemon has raised $363,000 in nondilutive capital and equity investments, Kennedy said. Sources include the Burton D. Morgan Foundation, FlashStarts, Great Lakes Innovation and Development Enterprise, JumpStart, Lemelson Foundation, National Science Foundation and Ohio Third Frontier.

While the intellectual property belongs to the university, Hedgemon was granted the exclusive license and is able to commercialise the projects. The company plans to either supply or license its helmet liner technology to a football helmet manufacturer.

"We see ourselves as an (research and development) company," Kennedy said.

The company received patent claims for future personal and material impact protection products, using the hedgehog-inspired modules. They include body armor, athletic shoe midsoles, child car seats, fall-protection flooring, transport cases, electronics housing and automotive paneling. The company is seeking foreign-territory approval.

"The total market for Hedgemon's impact protection technology exceeds $10 billion when other potential applications are factored," the company's proposal stated.