Tag: land animals

Move Over Band-Aids, the Gecko is Here.

Band-Aids and stitches have been around forever. They are safe and common ways to address everything from paper cuts to deep wounds. However, these technologies each have their own drawbacks and researchers have looked to nature to improve upon them; enter the gecko, more specifically their feet. The goal of these scientists was to use the adhesive properties of a gecko’s foot pads as an alternative method to hold wounds closed, but how does this work?

What Makes Geckos so Clingy?

A gecko’s foot pads are unique instead of relying on any sticky substance, their toes have rows and rows of setae. Setae as you can see below are essentially rows of microscopic hooks that can cling in one direction. This causes no damage to the surface and because of the ways the setae are oriented, they are easy to remove from the surface in one direction. This is what allows a gecko to both cling to and easily remove their feet from a surface, or in our case makes adhesives made with this technique both secure and easier to remove than their counterparts. 

Detailed up-close images of Setae arranged on a Gecko's foot
Wei Wang, Yang Liu & Zongwu Xie, Journal of Bionic Engineering (2021)


The Importance of Stickiness

Human skin is actually quite a rough surface that undergoes a lot of compression, tension and is further complicated by the existence of hair follicles and sweat. All of these factors make attaching anything like the gecko-based dry adhesive to the skin a daunting task. To get around this, bandaids rely on overpowering amounts of sticky substance and stitches are woven into the skin. This means that upon removal more damage and irritation to the wound can occurs. In a study the adhesive force of this technology was tested as well as the removal difficulty. It was found that this new method can achieve maximum closing forces slightly below that of sutures and is easier to remove than a bandaid of the same size. Notably, it does perform worse in wet or very humid conditions, so waterproof band-aids have a bright future.

The Design

A team of researchers published a study outlining the design, benefits, and drawbacks of a medical adhesive designed to mimic the gecko. This design encompasses the wound while providing a closing force to keep the wound closed. The amount of closing force imparted can be altered by changing both the number of legs and their thickness.

Adhesive designed with Setae closing a wound
Hadi Khoramishad, Mohammad Arjomandi, Romina Arjmandi, Tissues & Biomaterials Research Group (2019)

This is important because it means this method can be adapted to match the type of wound it is addressing. For a small cut a small adhesive with few legs can be used whereas, for a more serious wound, a larger adhesive layer with more, thicker legs will be used. This method also allows for air circulation allowing oxygen to reach to wound which promotes healing better than traditional methods. Using a gecko adhesive also minimizes wound irritation which can be a problem, especially for stitches and sutures which often cause irritation and even infection. Finally, this dry adhesive surface is biocompatible and can be made biodegradable. This means they will not react negatively with the skin and can safely dissolve in the body. This makes it a very desirable alternative to sutures which must be removed after insertion causing further wound irritation and requiring another visit to the doctor.

So while it may take a few years still don’t be surprised if you see dry adhesives for wound closings popping up on shelves; and when you see them know that they were inspired by the gecko. If you would like to learn more keep reading here.

You’re One Tough Nut To Crack!

On April 13, 2022, a video uploaded to YouTube titled The End broke the internet. A former Blue Sky Studios Employee, who over the years helped animate the Ice Age movie franchise, posted an unreleased short scene that depicted Scrat, the crazed squirrel from the series, finally catching and eating the acorn he spent more than a decade fighting and almost perishing over.

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Avoiding Cat-astrophe: How do Cats Land their Crazy Jumps?

Four panels showing the sequence of an American shorthair domestic cat jumping from the top of a fridge to a counter. The cat's body stretches long while in the air and curls up after contacting the counter.

Cats always land on their feet, or so the saying goes. Every cat owner has witnessed their feline make death defying jumps and walk away like it’s no big deal. 90% of cats can actually survive falling off of a high rise building. But how do they do it? How do cats absorb the impact of their leaps without sustaining injuries? 

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A Sticky Situation: The Forest’s Tree-Climbing Superhero

Photo by Pixabay on StockVault

As a child, did you ever watch with awe as Spider-Man climbed lofty buildings in New York City? This super-power has captivated audiences for decades because it seems impossible that a tiny fingertip could provide such great strength. However, the powerful and sticky toes of the tree frog bring this super-power to reality. Their toes have round pads that can cling to surfaces, both wet and dry, due to biomechanical forces. What causes their toes to be so sticky?

Read more: A Sticky Situation: The Forest’s Tree-Climbing Superhero

A microscopic view of the epithelial cells of a tree frog toe pad highlights the deep channels and raised polygonal micropillars on the epithelial surface. 
Polygonal epithelial cells of a tree frog toe pad with channels and micro-pillars. Modified from Kappl, Kaveh, & Barnes, Bioinspiration and Biomimetics 2016

The round toe pads of the tree frog are composed of four layers of surface cells known as epithelial cells. Epithelial cells line all surfaces of the body, including the external surfaces and internal cavities of the body, such as the inner surfaces of organs. The epithelial cells of the toe pad are shaped like hexagons and columnar. Columnar cells have a greater height than width and resemble small pillars. These microscopic pillars are separated from each other by channels filled with mucous. This unique structure creates a phenomenon known as wet adhesion.

The word “adhesion” likely prompts thoughts of everyday adhesives like glue and tape. But, what is wet adhesion? The molecules in liquids are attracted to each other and to the surface surrounding the liquid. In a small container, these attractions cause what are known as capillary forces. When a straw is placed in water, liquid climbs the side of the straw due to these forces. Wet adhesion is the attachment of two materials due to the presence of a liquid with capillary forces. A good example of wet adhesion is when a piece of plastic that is wet gets stuck to a glass table.

The pillar and channel surface of a tree frog toe are filled with mucous. Liquid fills the vertical channel and creates a layer of liquid between the pad and the surface.
Pillar channels filled with mucous create a layer of liquid between the pad and the surface. Modified from Zhang et al., Biosurface and Biotribology 2022

In the toe pads, the mucous secreted into pillar channels creates a layer of liquid between the pad and the external surface, which encourages capillary forces. The liquid layer has also been found to encourage viscous forces. Viscous forces are caused by the attraction between liquid molecules. The attractive forces resist the horizontal movement of liquid molecules when a force is applied tangent to the liquid’s surface. Capillary and viscous forces allow tree frogs to adhere to surfaces at steep angles without sliding off.

Recent research has also shown that frictional forces play a role in toe pad adhesion. The stiffness of the surface of toe pads is not uniform. The polygonal epithelial cells at the surface of the pad have a higher stiffness than the material below. The flexibility of the material below the surface allows for better contour of the pad to a surface. The enhanced interaction with the surface imperfections causes frictional forces to resist sliding and encourage adhesion.  

Photo by Pexels on Freerange Stock

The adhesive toe pads of tree frogs have inspired several engineering applications, including wet adhesive materials. Scientists are pursuing the fabrication of artificial materials that can mimic the characteristic micropillars of tree frog epithelial cells. For example, typical surgical tools, such as forceps, may struggle to effectively grasp softer tissues or increase the risk of tissue damage. Wet adhesive surgical graspers may provide a less abrasive method of holding soft tissues throughout a procedure. Tree frog-inspired wet adhesives may also be used to create sensors and monitors that can easily adhere to a patient’s skin. The study of wet adhesives has the potential to greatly benefit the medical field.      

Pacific Rim In Real Life?

How Close are we to a Pacific Rim Reality?

A picture of a kaiju infected robot
A photo from the movie Pacific Rim 2

Remember those giant hybrid kaiju-fighting robots from Pacific Rim where the brain of a kaiju (strange beast in Japanese) has successfully infected the mechanical brain of the robots and turned human’s greatest defense against them ? Well, it turns out, the boundary between science fiction and reality isn’t as far as we thought. A researched field “Necrobotics” has taken the world by storm and it is so new that Google is still highlighting “Necrobotics” as red. Imagine a world where nature’s most complex design is integrated into human’s innovation, leading to the most incredible biohybrid systems. If you are drawn the future application of this field or the potential harmony between biology and robotics, you’re in for a treat. In this blog post, we’ll be exploring the existing researches within Necrobotics and the future outlook on this unique field.

Necrobotics, a term derived from “Latinized form of Greek nekros” (relating to death ) and “robotics,” may sound a tad bit eerie, but it’s far from sinister. In fact, it’s all about bringing life to machines. The heart of the research is focused on producing biohybrid system that utilizes the intricate abilities of a living organism while combining with the precision and flawless decision making skills of a robot. Similar to our natural world, it draws inspiration from our environment such as the symbiotic relationship of Bees feeding on a flower’s nectar while carrying its pollen from plant to plant.

So, why should you be interested in this intersection of biology and technology? The applications are nothing short of astounding. One day, we will have biohybrid robots aiding in disaster relief events, enhancing our healthcare capabilities and assisting us in answering humankind most complex questions. These robots are able to mimic natural organism abilities, making them more adaptable, versatile, and resilient than conventional robots. From robotic limbs that respond to neural signals in the body to machines that slither like snakes, Necrobotics are in prime position to push humankind to the next level.

Gecko skin adhering to smooth surfaces
Photos from the article “Evidence for van der Waals adhesion in gecko setae”

Scientists and engineers have developed a variety of technology by studying organisms that have evolved over millennia of evolution. These technology include surface wettability modification based on lotus leaves and Namib beetles, adhesion mechanisms that mimic gecko toes, and even sensing for smart materials by imitating the color-changing chameleon and the humidity-sensitive pine cone. In order to inform the design of robots and actuators, researchers have also taken inspiration from the locomotion of aquatic and terrestrial animals, such as starfish, jellyfish, and cephalopod. Here is a famous example of dead spider corpse used as a mechanical claw.

In conclusion, these scientific topics may have been initially perceived as science fiction but it has quickly garnered attention and are becoming a crucial step for mankind to take. Future discoveries in this field will have the potential to redefine countless industries while acknowledge nature’s design. So if you’ve ever imagined a time where science and nature coexist, now is the perfect time to get excited about necroboticsᅳthe future is here, and it’s amazing.

Read more: Pacific Rim In Real Life?

Snakes: What makes them slither?

If you had no legs or arms, wouldn’t it be difficult to get from place to place? However, snakes don’t have any legs and they get around just fine! Almost all land animals had legs to propel themselves forward, so how do snakes move so effectively? The biology of a snake involves a series of ribs and muscles that contort a snake’s body to push itself forward. Not only does the snake’s internal makeup allow it to move, but also its exterior. Snakeskin has frictional properties which allow it to remain stationary along an incline with just a few scales in contact with a surface!

Snake moving from branch to branch.
Photo by Krzysztof Niewolny on pixabay.

A snake’s ability to slither across the ground is made possible by its ability to bend using a series of muscles along their body. The scientific term for this bending motion is lateral and vertical bending. A snake uses lateral bending to change direction or propel itself forward along a flat surface. Vertical bending is employed when a snake is pushing off a surface intending to move upward, such as in a tree or on a steep rocky slope. Using the terrain upon which the snake is traversing, the snake is able to propel itself forward by pushing off uneven ground, sand, branches, or other obstacles. 

Snakes have a series of hundreds of ribs that run along the entire length of their body. Not only do their ribs provide a firm foundation for the snake to push itself off of the ground, but they also provide structural support for the snake to traverse gaps along a surface such as holes, tree branches, or other places where a snake cannot use bending to move. With respect to slithering, the ribs of a snake allow it to bend and coil to get the best contact with the ground.

Close-up of snakeskin showing the layout of scales along the body of a snake.
Photo by Paul Brennan on pixabay.

However, it is not just the forces that snakes apply to the ground that allow them to move, but also the makeup of their skin. Snakeskin has frictional properties that allow them to get a better grip on the surface upon which they move. For example, if a surface is slippery or at a steep incline, a snake can increase the surface area their skin covers by changing the angle their scales come into contact with a surface. 

Understanding how snakes move without the use of legs is important for engineering applications. Legless robotics can be designed using the concept of the biomechanics behind the movement of snakes. For example, this could be implemented in terrestrial rovers that can travel across uneven terrain.  In addition, materials science applications for purposes of gripping can mimic snakeskin for higher friction abilities. This would be greatly beneficial for sports, military, or medical equipment where gripping ability determines overall usability. 

Video by Snake Discovery on Youtube
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Too Tall to Run: How a Giraffes Height Affects their Locomotion

Seeing a giraffe for the first time, one is amazed by their long necks and long legs, but do you ever wonder how their long skinny legs can support their large body mass as they move about? Studies have shown that a giraffe’s legs undergo a large ground reaction force when walking freely and an even larger ground reaction force when moving at a faster speed than walking.

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Deer Science, what’s changing my antlers and why are they important to you?

A deer is a mammal that is recognizable by the majority of people. Typically, the male deer or buck has the unique attribute of antlers. Antlers are made up of bone that develops, grows, and falls off each year.

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The hairy feet of the gecko

Have you ever thought about what it would be like to walk on walls? If you’ve ever watched a Spiderman movie or watched a gecko maneuver around its habitat, you probably have. While geckos don’t fight crime, their climbing ability is as fantastic as that of any superhero. Geckos have one of the most unique climbing adaptations of any animal, and scientists are examining the source of this ability to see if human technology could one day achieve something similar.

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