Written by Ethan Mann
Biomimicry design is a problem-solving approach that turns to nature for inspiration. The Biomimicry Institute defines it as an “approach to innovation that seeks sustainable solutions to human challenges by emulating nature’s time-tested patterns and strategies.” Nature’s processes and strategies have evolved to be efficient and holistic.
“In nature there is no such thing as waste. In nature nothing is wasted; everything is recycled.” -David Suzuki
You can find unique solutions from nature in commercial products today. A curious George de Mestral observed how burrs stuck to his dog, then invented Velcro. Geckos inspired adhesion technology. Self-cleaning lotus leaves sparked surface innovation, from water-repellent fabrics to self-cleaning sky-scraper windows. Now, biomimicry is leading to advancements in medical technology.
Learn more about shark biomimicry and how observations of marine life, and sharks, in particular, helped advance medical technology to prevent infection.
Shark Biomimicry: How Sharks Inspired Advanced Medical Technology
First, let’s start with urinary catheters. Yes, it’s a stretch from sharks to catheters, but this is where this problem started. Urinary catheters are one of the most commonly used medical devices and the most commonly infected medical devices. It turns out, preventing fouling, the accumulation of unwanted materials on surfaces, on the catheters following implantation is critical to reducing the risk of infection. It can lead to colonization by bacteria on the outside of the catheter. Notably, bacteria attaching to the outside of the catheter and moving along the catheter towards the bladder is a primary cause of Catheter-Associated Urinary Tract Infections (CAUTIs).
Here’s where the gap between human problems and nature’s solutionss comes into play:
Observe and Learn from Nature: What is Fouling?
Scientists observed that fouling occurs on many large marine species, except sharks. Marine fouling is the collection and growth of marine material that occurs on whales, sea turtles, and manatees. Imagine a whale’s underbelly or the fins of a sea turtle: they are often covered in barnacles. So, we know sharks are cool, but why are sharks clean and exempt from fouling?
Why Are Sharks Exempt From Fouling?
Sharks have adapted to develop a texture on their denticles to resist fouling.
In addition to the importance of the texture of shark denticles for reducing fouling, fluid forces along the texture and the replenishment of denticles are also likely to have an important role.
A Shark-Inspired Solution
With his team at the University of Florida in Gainesville, Dr. Anthony Brennan studies the impact of surface texture on biology. Initially, Dr. Brennan focused on understanding how bacteria attach to surfaces and which bacteria are most problematic in certain circumstances. Following the foundation of his company, Sharklet Technologies, Inc., Dr. Brennan focused on how the use of ordered microtextures impacted and/or prevented frequent infections on urinary catheters.
Sharklet sought to use a specific micropattern, or tiny ordered surface texture, developed in a specific method to prevent general fouling, bacterial attachment, and bacterial movement on the device.
Testing Micropatterns
He used models to test his hypotheses which allowed him to derive important predictive equations describing ordered micropatterns having specific surface energy impacts sensed by biological organisms under specific circumstances. First, we established the potential benefit of a micropattern in a situation with well-controlled laboratory studies. Then, we continued to challenge the situation with more rigorous experiments. We designed complex laboratory recreations of the problems. Finally, we tested the circumstances using simulation studies and clinical studies.
Studies on that device have progressed from simple laboratory tests, more complex laboratory tests, veterinary clinical studies, and even human clinical trials.
The first human trials presented at the American Urology Association meeting demonstrated less fouling and patients remarked that they experienced less pain with the advanced catheters.
Micropatterns: Sustainable Solutions Beyond Antibiotics
The use of textured surfaces is a preventative approach to infection control
The use of a texture that prevents attachment and propagation of bacteria is a more responsible approach than killing all bacteria on contact.
In addition, poorly deployed toxic approaches intended to kill germs leave “wounded” bacteria to pass on secrets to beating these kill technologies. This has contributed to the emergence of antimicrobial resistance. The use of a shark skin-like texture on medical devices or consumer products was a complete paradigm shift away from sterilization of surfaces through kill technologies.
Advanced Medical Technology and Surface Textures
The development of the urinary catheter with the sharkskin texture led to testing other applications of the micropattern to control infection mechanisms on other medical devices or even medical surfaces in hospitals. Eventually, using micropatterns to control medical device behavior led to investigating how variations of the micropattern could prevent complications. Imagine solving issues like clogging of tubes, blood clotting on devices, or poor healing mechanisms around implanted devices.
As we began to learn more about the benefits of additional applications, we developed more advanced micropatterns. We began tuning the micropattern to best fit a required medical need. Some circumstances required precise infection control while others needed improved fluid flow or control of human cells responsible for healing mechanism.
Is This Technology Available to the Public?
Catheters and other Sharklet medical products are not widely available on the market today, but as we scale to meet demands and complete clinical safety studies, we will find new ways to apply this technology. I predict that as we continue to enhance manufacturing for the development of ordered micropatterns we’ll continue to see more medical benefits.
From Shark Biomimicry Design to Bioinspired Thinking
Organisms in nature adapt to survive and that pressure forces advancements. As humans, we react to a very similar force. However, we use human reason to adapt as opposed to biological adaptation. The discovery that texture can be pivotal in product function when used correctly and a detriment, when used incorrectly, shows that an understanding of nature can lead to sustainable, preventative measures. Yet, the approach to understanding the impact of surface textures in the world around us is really what we’ve learned from sharks.
The field of biomimicry continues to expand: what was once strict repurposing of nature’s solutions has morphed into general inspiration regarding the very nature of solutions available. Companies are learning how woodpeckers can drill into bark and not experience concussions. Or how birds like the kingfisher are able to control rapid movement from air to water with limited drag. Others are using engineering designs of termites or other community organisms to building more efficient buildings.
We need to learn more about the world around us and let nature inspire paradigm shifts in medicine, science, technology, architecture, and engineering.
Learn more about Ethan Mann and his work.
