Bioinspiration — nature inspired research and how one scientist is redefining medical devices
The story doesn’t begin with a bang but it’s exciting nonetheless. In fact, the story begins when Jeffrey Karp, a bioengineer at Brigham and Women’s Hospital (BWH) in Cambridge, Massachusetts spotted a journal article on a colleague’s desk when he was working late one night.
The article spoke about how a bunch of researchers created a synthetic material which mimicked properties of gecko feet. The tiny hair-like pillars in the lizard’s feet help it stick to and detach from sheer surfaces without any problem. The potential uses of the material included gloves that would facilitate military personnel scale buildings with ease, so much like Spider-Man. In fact, it was the colour illustration of the friendly neighborhood super-hero that attracted Karp’s eye to the journal article.
Gecko comes to medicine
The man of ideas that he is, Karp’s first thought upon reading the article was to use the material and make a medical tape which could replace sutures and staples. At the time-this was in 2005, Karp was working with the renowned bioengineer Robert Langer. They were studying ways to produce biodegradable materials which could seal wounds within the human body. The envisioned tape could even be used for intricate surgical procedures- like tying together the small intestine during gastric bypass surgery.
Enthused though he was with the idea it didn’t take long for Karp to find that simply relying on friction between the hair-like pillars to make the tape stick wouldn’t work. For a gecko, that might suffice, but to bind live human tissue within the body, something way stronger would be required.
Karp tried a few things- like coating the surface of the tape with a glue and placing the pillars closer together on the surface of the tape. But much like Peter Parker’s earlier attempts at shooting the web out of his wrists as a perfect projectile, he failed.
The next thing Karp did worked-he moved the pillars apart again and then coated each pillar with a glue. This time when the tissue came in touch with a pillar, it stuck.
Three years after he saw the article, Karp was named one of the top innovators in the world under 35 by MIT’s Technology Review magazine.
Another example of Karp’s innovation came a few years ago. His attempt, this time was to use the jellyfish as an inspiration for improving the design of a blood analysis device which could detect if a cancer has metastasized after a tumour is removed. The devices that exist at present for the purpose are small rectangular chips. The blood would flow through the top of the device, the bottom would be lined with antibodies. These antibodies could attach to any cancerous cells that may be present in the sample. It’s possible to see if a blood sample contains cancerous cells by looking within the chip under a microscope.
One issue with these devices is that the blood flowed too fast and far above the antibodies-so even if there were cancerous cells, they may not cling. Later versions of the device had the distance between the top and bottom shortened. However, this meant that the blood sample needed to be smaller which led to less accurate results. Karp’s idea was to force the cancerous cells to slow down, thereby making then attach better to the antibodies. To this end, instead of lining the device with antibodies, Karp made synthetic jellyfish-like tentacles made of DNA. Each tentacle was about one-tenth the width of a human hair and was imbibed with a capturing agent which targets the tumour cells and grabs them. Testing an early prototype, Karp found that the new design can raise the blood flow by 10 times. This makes it more likely that cancerous cells are detected accurately.
The future according to the bioinspirationalists
Though there are other research labs dedicated exclusively to bioinspiration-like Don Ingber’s Wyss Institute at Harvard University, Karp’s is one of the few that focuses on medical research.(The Wyss Institute, for instance has over 15,000 patents in disciplines ranging from medicine to robotics).
Among the areas where Karp hopes to solve issues with bioinspiration include cell migration, wound healing and immune response. But when at a biomedical conference after he spoke about his lab, people only seem interested in his gecko tape, Karp decided to focus more on medical devices.
Now 40, Karp has his own lab at BWH. He is a bioinspirationalist- someone who turns to nature for scientific solutions. Considered as a pioneer in the field the gecko tape was Karp’s very first bioinspired invention. The projects the researcher is currently involved in include surgical staples inspired by porcupine quills and a surgical glue that has for inspiration the sticky secretions of marine worms-something strong enough to bind tissues within main organs like the heart.
Earlier in 2016, the surgical glue developed by Karp became part of a human clinical trial in Paris. Unlike surgical glues presently available in the market, his invention actively repels blood. This makes it ideal for sealing holes in intestinal tissue, blood vessels and even bone. The fact that it’s much sturdier means that surgeons can use it to fix cardiac defects without open heart surgery. In other words, it has the potential to transform how surgery is performed.
Mimic and improve
For Karp and others working in his field, nature often provides answers to key scientific and medical problems. The approach also enables scientists to access a large number of solutions which have been perfected after millions of years of trial and error testing. As Karp puts it, the appeal of bioinspiration is in the idea that every living creature alive today is here because it tackled a large number of challenges. In other words, we are surrounded by solutions.
Leif Ristroph, an Assistant Professor of Mathematics at New York University’s Courant Institute cites the case of the leaf as nature’s solar panel as a great example of bioinspiration.
A great example of bioinspiration is how Eiji Nakatsu, an engineer with the Japan Railways Group that operates the Shinkansen bullet train fixed a peculiar problem in the early 2000s. Whenever the bullet train passed through a narrow tunnel at a very high speed, the atmospheric pressure created low-frequency waves which spread out and created vibrations in the air. The vibrations were powerful enough for residents living 400 meters away from the railway line to complain about the noise.
Incredibly enough, it was from his weekend hobby of birdwatching that Nakatsu got the solution. Particularly, he was inspired by the kingfisher. The bird’s long and flat beak enables it to dive from the air into the water-from a low resistance area to a high resistance area. This the bird does with little disturbance so that its prey won’t be alerted. So Nakatsu redesigned the nose of the Shinkansen 500-series and made it longer and flatter. This helped reduce the air pressure by 30%
Even though such stories are cited vociferously by supporters of bioinspiration, Karp’s idea is not to copy nature directly. Rather, he likes to see what works and then improve in it. Adrian Thomas, a Professor of Biomechanics in the Zoology department at Oxford University elaborates that the key is to analyse the solution that evolution has converged on, and then take advantage of the principles in an engineering context. The obvious mistake, according to him is to copy nature because by using the best engineering materials, it’s possible to do much better than nature.
The challenge of turning invention into products
Karp got a chance for his next innovation when in August 2009, he received an email from Pedro J del Nido, a specialist in cardiac surgery at Boston Children’s Hospital. The problem he faced was that whenever he attempted to suture a hole, the surrounding tissue would tear.
Karp was excited by the problem though he didn’t have a clear idea of how to solve it. The gecko tape could seal things like gastrointestinal tracts and tissue. But the heart isn’t stationary, moving quite fast and violently. This meant the adhesive must be real strong. Karp didn’t know of any surgical glues which would suffice. Also, surgical glues could sometimes have harmful side-effects.
Realizing that to help del Nido, he would need more than just a lab solution, he decided to build a network comprising entrepreneurs, patent attorneys, venture capitalists, business managers and consultants. In the next years, he went about building this network which could help bring about not just an invention but also a commercially viable product. In his own words, “I wanted to make it in such a way that as soon as I came up with an idea, all I’d have to do is just fire off an email to the right person and that would be it.”
In early 2011, with the aid of one of his graduate students, Maria Pereira, Karp has developed a prototype of what could be a solution to Pedro del Nido’s problem- the problem of sealing the holes in children’s hearts.
Quite possibly, if proven successful, it could go to mass production thanks to the network of supporters Karp has created. And many more could come out of his lab.
