Resilient Vascular Stent Inspired by the Human Vascular System

Innovation: Industry

Veryan

2015

Image: Pixy / Public Domain - No restrictions

Prevent Fracture/Rupture

High force impact or stress can cause materials that comprise living systems to separate into two or more pieces (called fracturing) or to break or burst suddenly (called rupturing). For example, a scallop prevents structural failure from fracture because its shell is comprised of two materials of varying stiffness. When a crack moves from the scallop’s stiff material to the less stiff one, the latter reduces the force at the tip of the crack, thereby stopping it from spreading farther.

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Cycle Nutrients

In ecosystems, there is no such thing as waste. Instead, one organism’s waste can be considered as another organism’s resource, and the cycling of nutrients may be the most important form of recycling in living systems. But sometimes those nutrients are transformed by one organism into a form that isn’t readily used by other organisms. For example, lignin is a complex organic molecule found in the cell walls of plants. In a forest, it’s one of the hardest molecules to break down in woody vegetation. Therefore, ecosystems include organisms that are particularly well-adapted to break down different types of nutrients. In the case of lignin, some fungi and bacteria release lignin-modifying enzymes that can break down the lignin to form carbohydrates and other life-supporting chemicals.

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Modify Size/Shape/Mass/Volume

Many living systems alter their physical properties, such as size, shape, mass, or volume. These modifications occur in response to the living system’s needs and/or changing environmental conditions. For example, they may do this to move more efficiently, escape predators, recover from damage, or for many other reasons. These modifications require appropriate response rates and levels. Modifying any of these properties requires materials to enable such changes, cues to make the changes, and mechanisms to control them. An example is the porcupine fish, which protects itself from predators by taking sips of water or air to inflate its body and to erect spines embedded in its skin.

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Manage Mechanical Wear

A living system is subject to mechanical wear when two parts rub against each other or when the living system comes in contact with abrasive components in its environment, such as sand or coral. Some abrasive components are a constant force, such as finger joints moving, while others occur infrequently, such as a sand storm moving across a desert. Living systems protect from mechanical wear using strategies appropriate to the level and frequency of the source, such as having abrasion-resistant surfaces, replaceable parts, or lubricants. For example, human joints like shoulders and knees move against each other all day, every day. To protect from mechanical wear, a lubricant reduces friction between the cartilage and the joint.

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Manage Shear

The effect of shear stress on a living system is parallel internal surfaces sliding past each other. Slippage occurs in parallel with the force. Think about holding two wooden boards on top of each other and sliding one to the right and the other to the left. This may be easy until you add glue, which increases their shear strength and makes them harder or impossible to slide. Shear can occur in solids, liquids, and gases. Living systems must increase their shear strength to overcome these types of forces. For example, darkling beetles lock their wings together in flight to prevent lateral movement by using many small hairs on each wing. These hairs interlock to provide shear strength, just as two hair brushes put together would be difficult to slide past each other.

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BioMimics 3D: The Swirling Flow Stent
933.3 KB PDF

Patents

US8226704B2
1.1 MB PDF

BioMimics 3D Swirling Flow Stent from Veryan improves the performance of vascular stents by incorporating a unique 3D helical geometry.

Benefits

Reduced irritation and injury
Improved performance
Fracture-resistant

Applications

Medical implants

UN Sustainable Development Goals Addressed

Goal 3: Good Health & Wellbeing

The Challenge

Humans are both living longer and becoming more vulnerable to many health conditions. Vascular stent demand is increasing due to a large number of people with underlying health issues, such as obesity, diabetes, and other conditions that lead to peripheral arterial disease. For coronary intervention, the use of stents has increasingly replaced bypass surgery. Traditional stents straighten arteries and disturb blood flow, creating shear stress that can damage the tissue. This can complicate the healing process after surgery and lead to stent failure.

Innovation Details

The BioMimics 3D Swirling Flow® Stent is self-expanding and has a unique 3D geometry that gives it a slight shape, mimicking the natural shape and geometry of the human vascular system. This results in stents that are more flexible, more kink-resistant, and more fracture-resistant than straight stents. They also impart the swirling flow of blood through the stent, which has been shown to reduce restenosis. The stent also improves biomechanical compatibility and reduces vascular irritation and injury.

Illustration of the BioMimics 3D Swirling Flow® Stent. Photo: Veryan.

Biological Model

The body’s natural defence against the propagation of vascular disease is to generate smooth swirling flow through the arteries, particularly at arterial junctions. This is achieved by the gentle helical geometry of the arterial system. Natural swirling flow eliminates zones of high and low wall shear, cross-mixes nutrients to ensure optimum supply to the vessel wall and sweeps areas of potential stagnant flow. Additionally, the correct level of stable flow against the artery wall activates important defensive genes, which further prevent disease proliferation.

See Related Strategy

red, blue, white, and pink graphic image of the circulatory system

Biological Strategy

Why Curvy Blood Vessels Are More Efficient

Animals

Arteries of humans enhance transport of molecules between blood and the wall by having a helical structure.

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