The year in biomimicry: Robots inspired by cheetahs and moon jellies

The Biomimicry Column

The year in biomimicry: Robots inspired by cheetahs and moon jellies

It’s time for the fourth annual Tommies, my list of notable bio-inspired ideas of 2012. As always, I have organized the list by the organisms that inspired the inventions or discoveries. Let me know if you have a favorite I might have missed. You can find the Tommies from 2011 here, the 2010 list here, and the 2009 awards here.

1. The cheetah: Boston Dynamics, a private company with funding from the U.S. Department of Defense DARPA Maximum Mobility and Manipulation (M3) program, has made and tested the world’s fastest land robot, a four-legged machine based on the African cat. Critical to the performance was the mimicking of the flexible spine of the Cheetah, which allows for hyperextension, and the coordination of the striding legs.

The machine recently set the land speed record for robots at 28.3 mph, faster than the world’s fastest human (Usain Bolt at 27.8 mph over 100 yards in 2009). The robot is not autonomous: An off-board hydraulic pump and a boom power and steady it as it runs on a treadmill. A free-running version, powered by a gasoline engine, is planned. When it does begin trials, it will still be far behind its natural mentor, which can reach speeds of up to 70 mph. All-terrain robots that are fast and reliable would be a distinct tactical advantage to military ground forces, and could be used for other hazardous work like disaster relief and medical rescue.

2. The sunflower: Researchers from Massachusetts Institute of Technology and RWTH Aachen University have studied the geometrical array of sunflower florets and used the information they gained to improve the efficiency of a concentrated solar power (CSP) plant, PS10, in Andalusia, Spain.

In a CSP, ground mounted mirrors reflect and concentrate sunlight onto a central tower where water is boiled by the resultant heat to make steam for generators. One drawback of this sustainable energy production method is the large amount of land area needed for the mirror array. The team designed the array with a Fermat spiral pattern in which each mirror was angled at 137 degrees. This arrangement resulted in a 20 percent space savings by simply changing the geometry of the layout.

3. Bacteria: University of Oxford scientists have developed a process to manufacture a superglue for nanoscale molecular construction. The glue was inspired by  a unique protein, FbaB, that is produced by Streptococcus pyogenes, the same germ that can cause strep throat. The protein has a 3D structure that is stabilized by strong covalent bonds, and the researchers were able to manufacture a new, engineered version that is simpler and smaller. They were able to split this bond into its two parts and rejoin them at will, like a two-part glue. The bond is fast and irreversible, as strong as a carbon nanotube, and highly resistant to time, stress and chemicals. Itis not affected by temperature or pH. Importantly, the bond only sticks to itself and not to other molecular surfaces, so is very controllable.

The discovery has wide potential application for the biomedical field. It appears to be an important new fabrication tool in the development of modular molecular construction, the assembling of proteins and enzymes like a set of Legos. This could be used to assemble nanofactories, or be used in tissue reconstruction.  It may be more immediately important in research, though, since synthetic structures could be attached to working parts of cells without damaging them, or being disengaged by them.

4. The brittlestar: Chemists from the University of Konstanz, the Max Planck Institute of Colloids and Interfaces, and two Korean institutions have developed a process for the simplified manufacture of microlens arrays. These are found naturally on the Brittlestar, a sea creature related to the starfish.

The Brittlestar is known for its self-assembly of biomineral lenses from calcium carbonate from surrounding seawater. It uses these arrays to change color according to light conditions. The scientists used a saturated calcium solution, carbon dioxide from air and a broadly available surfactant (a soap molecule), to “grow” the array of hemispherical lenses. The techniques of close-packing and self-assembly greatly improved the manufacturing process.

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Microlens arrays are used in cell phone cameras and in the miniaturization of optical systems, where the focusing of light with a precision of a millionth meter or working with very small wavelengths is needed. The new process could also be used to generate anti-reflex coatings as found on eyeglasses. The chalk lenses produced this way have shorter focal lengths compared to the plastic lens arrays now made by the more expensive lithography method and can be transferred to other surfaces by a simple dip coating.

5. Moon jelly: Another creature from the sea, Aurelia aurita -- also called the moon jelly  -- has inspired a “softbot” called Robojelly designed by a team of scientists based at Virginia Tech and the University of Texas at Dallas. The robot is made of a nickel-titanium memory alloy wrapped in carbon nanotubes and coated with a platinum catalyst, all packed under a silicone-based substance designed to mimic the jelly-like layer between the creature’s outer layer of cells. Its artificial muscles are powered by heat produced from the reaction of platinum with the oxygen and hydrogen gas found in the surrounding water.

This means Robojelly could, theoretically, swim forever, since its motion is powered by a chemical reaction with its environment. This kind of energy saving mechanism has potential applications in long-running marine sensors, sampling robots and navigation aids, where low power over a long time is needed.

6. The silk moth: Bombyx mori weaves a cocoon that is strong, moisture-resistant, biocompatible and stable at high temperatures. Experimenters at Tufts University School of Engineering in Boston have developed a potentially revolutionary packaging type inspired by the moth. 

The packaging has the potential of eliminating the so-called “cold chain” of delivery now required to preserve vaccines through refrigeration before use. Health experts estimate that as much as half of all vaccines are lost currently due to spoilage by bacteria or loss of potency.

By creating a gel and matrix material with the silk proteins, the scientists have been able to keep labile vaccines and antibiotics fresh for six months at temperatures up to 60 degrees Celsius, all without the energy, expense and expertise needed for refrigeration. While this could be seen as an example of bio-utilization, rather than bio-inspiration, the innovation here is in mimicking the molecular array of silk bonding as a scaffold to protect a material from the environment, and in suffusing a vaccine into it. Moreover, developers have been able to manufacture a range of devices from the silk, including microneedles that allow the drugs to be stored and administered in a single device.

7. The cat: Its retractable claws are a marvel of clever engineering, and designer Yoshi Fukaya has turned the humble thumbtack into a friendlier device thanks to his feline study. His “Biomimicry Pins” are sheathed in a hollow silicone jacket that squashes when pushed against a wall, allowing the pin to puncture the surface more easily.

8. The firefly: The well-known glow from this insect is an example of bioluminescence and is caused by the reaction of luciferin with the enzyme luciferase. A team at Syracuse University has been able to produce a stronger light from this method by chemically attaching genetically manipulated luciferase enzymes directly to the surface of a nanorod structure made of semiconductor metal. The innovation is in the scale at which the team worked, allowing a decrease in the distance between the enzyme and the surface of the rods.

Next page:  The rest of the top 10

The new method has increased brightness by 20 to 30 times, requires no energy input, and is able to produce different colors (something its natural mentor is unable to do). The infrared range appears to be the most efficiently produced and this suggests applications in night-vision goggles, cameras and other electronics. The team believes the process could be applied at a larger scale and eventually be used in zero-energy lighting displays.

9. Plant leaves: The folds and valleys of a typical plant leaf have inspired a team of engineers from Princeton University to improve the performance of a cling-film solar cell. The folds guide and retain light within the photo-active regions of photovoltaics and have increased light absorption by as much as 600 percent in the infrared region of the spectrum. The engineers used ultra-violet light to cure a layer of liquid photographic adhesive, alternating the speed of curing to modulate different thicknesses. The folding also improved the strength of the plastic cells and allowed light collection to continue unabated when the cell was folded. This type of performance suggests eventual applications in electricity-producing fabrics and other flexible material

10. Human antibodies: When infection occurs in our bodies, special cells, called lymphocytes, are able to make chemical antibodies. These antibodies attach themselves to specific invaders or antigens and allow what are known as "complement proteins" to pierce the membranes of the foreign cells and destroy them.

A team from the Wyss Institute at Harvard University has made a nanorobot that acts in a similar way. It is constructed from DNA in a clamshell shape held shut with a special DNA lock. The lock is designed to recognize certain kinds of cancer cells, and when it encounters them, the robot springs open and exposes the antibody payload to the surface of the antigen.

The innovation in the approach is the ability to identify a foe and carry a payload to an effective site. The nano-bot is an example of  ‘DNA origami” in that the strands are folded into a useful shape, in this case an open-ended box that is turned inside-out in order to deliver its charge. The team has been able to successfully target and destroy lymphoma and leukemia cells in the lab setting. While the process is not yet practical within the human blood system at the scale necessary for treatment, the potential is great for the kind of targeted treatment long aspired to.

We have had a wide range of scales and applications in our selection this year and it shows what a rich field bio-inspired design and development continues to be. Congratulations to all our clever and hard-working inventors, designers and explorers!

Photo of cheetah stretching provided by KA Photography KEVM111 via Shutterstock.