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IBT-04: Bionanotechnology

Submitted by: Apratim KhandelwalEn roll Number: 12118017Branch: Metallurgical and Materials Engineering.

Biomimicry assignment: Sea Urchins

Submitted to:Dr. P. Gopinath

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Contents

• Emulated Species• Important features• Application• Current Research• Future Scenario• The main Idea• Feasibility / Facts

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Introduction-Sea Urchins

Ever seen these small, spiny, colourful- round creatures living in the depth of the ocean?• Usually are 1.2 to 3.9 inches in dia.• Body is covered with either spines or

strong shell.

• There are around 200 species of sea urchins of different shapes, sizes and colours.

• These images show some regular/usual sea urchins.

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Important Features

Their body is radially symmetrical; possess a five fold symmetry. Their shell design is a biologically and mechanically stable 3-D fractal

(including the interesting fractal designs on the shell). The spine like structures on the outer body are used for protection,

collecting food and clearing path. They have five pairs of tube feet at the bottom to facilitate adhesion

to rocks, movement and hunting. They have two openings one at the bottom (mouth) and the other

vertically above it. The mouth has five hollow teeth which are sharp enough to chew

stones and are used for anchoring also. They have no eyes and the whole body act as a compound eye. The whole body is sensitive to touch, light and chemicals; used for

avoiding CO2 contact and enhancing shell life.

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Applications (current)BIONIC DOME: Mimicking the sea urchin’s skeleton using advanced computer based simulations.

What makes it stable?:The five fold symmetry and the ‘oblate’ shape of the outer body. This kind of design distributes any kind of stress evenly on the surface of sea urchins body making it more stable and stronger. The reason why sea urchins can withstand pressure at a depth of 6000 m.

The natural fractal designs on the outer body, copied for creating various architectural designs and structures.A further application can be to design roofs and buildings (mimicking the ‘sand dollar’) that can resist hail storms or other storms.

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Applications (current) Researchers at Newcastle University, UK, discovered that one of the natural ability of the sea

urchins is to absorb CO2 and convert it into less harmful carbonate. They use Ni to do so. Now this can be used as an effective model for capturing and converting one of the major

green house gases.

A CCS (Carbon Capturing System) can be implanted in each industry. Feasibility: The plus points in using Ni is that it carries on working regardless of the pH and

because of its magnetic properties it can be recaptured and reused from time to time.

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Applications (current) Despite constant grinding and scraping on stones, sea

urchin’s teeth never ever loose their sharpness. Researchers at the University of Wisconsin-Madison

discovered that these are made up of crystals of some super hard calcite nano-cement which have layers of weaker organic materials between them.

It is the arrangement of these nano crystals that make these tooth ‘self sharpening’.

Application: The orientation/composition of these crystals can be mimicked for making the present machinery tools which will require no honing.

The spines also show similar characteristics, these are porous, hollow single crystals of magnesium rich calcite with a three dimensional meshwork design. Single crystals show promising mechanical properties.

Applications (future scenario) The whole body of the sea urchin act as one compound eye. Researchers discovered that the ‘tube feet’ of urchins has six genes for light sensitive proteins

called ‘opsins’. The urchin has its own version of the master gene ‘Pax-6’, which governs the development of

human eyes.

In 2014, biological engineers in MIT created a new computer model that allows them to design the most complex three-dimensional DNA shapes.

Application: These genes can be mimicked using the advanced computer model simulations. The gene amplification and expression processes can be used to generate a new genetic

material, which can revolutionize the branch of Ophthalmology.

http://rspb.royalsocietypublishing.org/content/early/2011/03/28/rspb.2011.0336

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The “Big” Idea

Underwater military drones!!

‘Sea Urchin’ Submarines…!!!

Underwater excavators..!!!

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Supporting Facts/ Feasibility

The interior of the sea urchin is mostly hollow as it lacks a proper nervous system. The interior can be mimicked to some extent to create a compatible structure with the

outer shell. The hollow structure will give an increased mobility and fuel efficiency. The main aim is to apply the existing mechanics for a submarine to create this kind of

submarine/drones.

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Supporting Facts/ Feasibility

The oblate shape along with the hollow structure gives a mechanically stable structure for underwater situations.

The stress distribution over the shell is even, along with the even ‘hydraulic pressure distribution’ , preventing shell from cracking even at a depth of 6000 m.

The oblate shape helps the urchin to remain upright. Proper arrangement of spines along with this oblate shape can give sustainable

mechanics for the underwater instruments.

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Supporting Facts/ Feasibility

The spines help in protection from predators, clearing path and collecting food. If a ball and socket arrangement for implanting spines is used then the spines can serve a lot

of purpose. This proper arrangement can reduce the lift and drag forces in the moving water. The spines can be made of the same microstructural orientation as in the urchin, which will

give them high strength to weight ratio. Since the spines are hollow and consists of self healing capabilities due to the bio-minerals.

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Supporting Facts/ Feasibility

Sea urchin inspired bio adhesives can be used for the extended grip on the ocean surface. The adhesive is functional under water and can easily displace water, ions and weakly bound

poly-ions. These things can be rarely achieved by synthetic adhesives. In addition to this, the tube feet has a mechanism for releasing a de-adhesive. Emulating these chemical and mechanical processes for maintaining an attachment-

detachment cycle can revolutionise the underwater anchoring systems. Especially for the underwater excavators.

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Supporting Facts/ Feasibility

The tube feet help in the movement also. They use a water vascular system for movement. Which include, alternately contracting the muscles (pumping action) that force water into the

tube feet, causing them to extend and push against the ground, then relaxing to allow the feet to retract.

The same mechanism can be used for movement of the underwater submarines. The two holes (at top and bottom) can create the required hydraulic pressure for pumping

the water out of the tubes attached to the submarine.

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Supporting Facts/ Feasibility The outer material: the use of Ni alloys in

making the outer shell of the under water machines can prove to be very useful.

Both in terms of solving CO2 problem and providing resistant to corrosion.

The loss of Ni in the metal alloy with time can be tackled by using magnets.

The analogy of using single crystal teeth for digging purposes in oil excavators.

Also to enhance the anchoring of the underwater drones.

The body of a ‘Shingle Urchin’ is practically resistant to waves.

So instead of “Eating” them lets mimic them.

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Thank You