This work is supported by Multi-University Research Initiative through the Air Force Office of Scientific Research of the United States (AFOSR-FA9550-15-1-0009) (M. B. F., S. E. N., J.-Y. J., J. M). Collection of pink sea urchins was supported by the University of California Ship Funds and the US National Marine Fisheries Service (K.N.S., J.R.A.T). The authors acknowledge the following people: Prof. Jerry Tustaniwskyj for helpful suggestions during development of the bioinspired Aristotle's lantern sampler, Prof. Marc A. Meyers (UCSD, Dept. of Mechanical and Aerospace Engineering, Materials Science and Engineering Program), Prof. Robert L. Sah and Esther Cory (UCSD, Dept. of Bioengineering), and Dr. Maya deVries (Marine Biology Research Division, Scripps Institution of Oceanography). We also thank undergraduate students Sze Hei Siu, Jerry Ng and Ivan Torres for polishing urchin teeth cross-sections.

1. Biological Materials Science
<ol>
	<li>Wear personal protective equipment (i.e., gloves, safety glasses and lab coat) and follow all applicable safety procedures for using dissecting tools.</li>
	<li>Rinse off the forceps and scalpel with distilled water to use for dissection.</li>
	<li>Thaw a frozen pink sea urchin at RT for 1 hr. Place a thawed specimen in a glass dish with sufficient space to be able to maneuver the urchin and cutting tools. Turn the urchin upside down so that the teeth tips face up.
	<o...

<ol>
	<li>Nalla, R. K., Kruzic, J. J., Ritchie, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+origin+of+the+toughness+of+mineralized+tissue:+Microcracking+or+crack+bridging?.">On the origin of the toughness of mineralized tissue: Microcracking or crack bridging?.</a> Bone. 34 (5), 790-798 (2004).</li><li>Ritchie, R. O., Buehler, M. J., Hansma, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasticity+and+toughness+in+bone.">Plasticity and toughness in bone.</a> Physics Today. 62 (6), 41-47 (2009).</li><li>Seki, Y., Schneider, M. S., Meyers, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+and+mechanical+behavior+of+a+toucan+beak.">Structure and mechanical behavior of a toucan beak.</a> Acta Mater. 53 (20), 5281-5296 (2005).</li><li>Feng, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Super-hydrophobic+surfaces:+From+natural+to+artificial.">Super-hydrophobic surfaces: From natural to artificial.</a> Adv. Mater. 14 (24), 1857-1860 (2002).</li><li>Sun, T. L., Feng, L., Gao, X. F., Jiang, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioinspired+surfaces+with+special+wettability.">Bioinspired surfaces with special wettability.</a> Acc. Chem. Res. 38 (8), 644-652 (2005).</li><li>Feng, X. J., Jiang, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+creation+of+superwetting/antiwetting+surfaces.">Design and creation of superwetting/antiwetting surfaces.</a> Adv. Mater. 18 (23), 3063-3078 (2006).</li><li>Arzt, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biological+and+artificial+attachment+devices:+Lessons+for+materials+scientists+from+flies+and+geckos.">Biological and artificial attachment devices: Lessons for materials scientists from flies and geckos.</a> Mat. Sci. Eng. C. 26 (8), 1245-1250 (2006).</li><li>Geim, A. K., Dubonos, S. V., Grigorieva, I. V., Novoselov, K. S., Zhukov, A. A., Shapoval, S. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfabricated+adhesive+mimicking+gecko+foot-hair.">Microfabricated adhesive mimicking gecko foot-hair.</a> Nat. Mater. 2 (7), 461-463 (2003).</li><li>Munch, E., Launey, M. E., Alsem, D. H., Saiz, E., Tomsia, A. P., Ritchie, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tough,+bio-inspired+hybrid+materials.">Tough, bio-inspired hybrid materials.</a> Science. 322 (5907), 1516-1520 (2008).</li><li>Launey, M. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Designing+highly+toughened+hybrid+composites+through+nature-inspired+hierarchical+complexity.">Designing highly toughened hybrid composites through nature-inspired hierarchical complexity.</a> Acta Mater. 57 (10), 2919-2932 (2009).</li><li>Launey, M. E., Munch, E., Alsem, D. H., Saiz, E., Tomsia, A. P., Ritchie, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+biomimetic+approach+to+the+design+of+high-performance+ceramic-metal+composites.">A novel biomimetic approach to the design of high-performance ceramic-metal composites.</a> J. R. Soc. Interface. 7 (46), 741-753 (2010).</li><li>Jelinek, F., Smit, G., Breedveld, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioinspired+spring-loaded+biopsy+harvester-Experimental+prototype+design+and+feasibility+tests.">Bioinspired spring-loaded biopsy harvester-Experimental prototype design and feasibility tests.</a> J. Med. Devices. 8 (1), 015002 (2014).</li><li>Jelinek, F., Goderie, J., van Rixel, A., Stam, D., Zenhorst, J., Breedveld, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioinspired+crown-cutter-The+impact+of+tooth+quantity+and+bevel+type+on+tissue+deformation,+penetration+forces,+and+tooth+collapsibility.">Bioinspired crown-cutter-The impact of tooth quantity and bevel type on tissue deformation, penetration forces, and tooth collapsibility.</a> J. Med. Devices. 8 (4), 041009 (2014).</li><li>Reich, M., Smith, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Origins+and+biomechanical+evolution+of+teeth+in+echnoids+and+their+relatives.">Origins and biomechanical evolution of teeth in echnoids and their relatives.</a> Palaeontology. 52 (5), 1149-1168 (2009).</li><li>Scarpa, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Modelli di Bionica, Capire la Natura Sttraverso i Modelli. , (1985).</li><li>Trogu, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bionics+and+Design:+Pure+and+Applied+Research.">Bionics and Design: Pure and Applied Research.</a> , (2014).</li><li>Porter, M. M., Adriaens, D., Hatton, R. L., Meyers, M. A., McKittrick, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioexploration:+How+engineering+designs+help+elucidate+the+evolution+of+seahorse+tails.">Bioexploration: How engineering designs help elucidate the evolution of seahorse tails.</a> , (2015).</li><li>Porter, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bioinspired Design: Magnetic Freeze Casting. , (2014).</li><li>De Ridder, C., Lawrence, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Food+and+feeding+mechanisms:+Echinoidea.">Food and feeding mechanisms: Echinoidea.</a> Echinoderm Nutrition. , (1982).</li><li>Killian, C. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-sharpening+mechanism+of+the+sea+urchin+tooth.">Self-sharpening mechanism of the sea urchin tooth.</a> Adv. Funct. Mater. 21 (4), 682-690 (2011).</li><li>Kier, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolutionary+trends+and+their+functional+significance+in+the+post-paleozoic+echinoids.">Evolutionary trends and their functional significance in the post-paleozoic echinoids.</a> J. Paleo. 48 (3), 1-95 (1974).</li><li>Wang, R. Z., Addadi, L., Weiner, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+strategies+of+sea+urchin+teeth:+structure,+composition+and+micromechanical+relations+to+function.">Design strategies of sea urchin teeth: structure, composition and micromechanical relations to function.</a> Phil. Trans. R. Soc. B: Biol. Sci. 352 (1352), 469-480 (1997).</li><li>Ma, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+grinding+tip+of+the+sea+urchin+tooth+exhibits+exquisite+control+over+calcite+crystal+orientation+and+Mg+distribution.">The grinding tip of the sea urchin tooth exhibits exquisite control over calcite crystal orientation and Mg distribution.</a> Proc. Natl. Acad. Sci. U.S.A. 106 (15), 6048-6053 (2009).</li><li>Markel, K., Gorny, P., Abraham, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microstructure+of+sea+urchin+teeth.">Microstructure of sea urchin teeth.</a> Fortschritte der Zoologie. 24 (2-3), 103-114 (1977).</li><li>Andrietti, F., MD, C. a. r. n. e. v. a. l. i. . C. a. n. d. i. a., Wilkie, I. C., Lanzavecchia, G., Melone, G., Celentano, F. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+analysis+of+the+sea-urchin+lantern:+the+overall+system+in+Paracentrotus+lividus.">Mechanical analysis of the sea-urchin lantern: the overall system in Paracentrotus lividus.</a> J. Zool., London. 220, 345-366 (1990).</li><li>Ellers, O., Telford, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forces+generated+by+the+jaws+of+Clypeasteroids+(Echinodermata:+Echionoidea).">Forces generated by the jaws of Clypeasteroids (Echinodermata: Echionoidea).</a> J. Exp. Biol. 155, 585-603 (1991).</li><li>Candia Carnevali, M. D., Wilkie, I. C., Lucca, E., Andrietti, F., Melone, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Aristotle's+lantern+of+the+sea-urchin+Stylocidaris+affinis+(Echinoida,+Cidaridae):+functional+morphology+of+the+musculo-skeletal+system.">The Aristotle's lantern of the sea-urchin Stylocidaris affinis (Echinoida, Cidaridae): functional morphology of the musculo-skeletal system.</a> Zoomorphology. 113 (3), 173-189 (1993).</li><li>Wilkie, I. C., Candia Carnevali, M. D., Andrietti, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+properties+of+sea-urchin+lantern+muscles:+a+comparative+investigation+of+intact+muscle+groups+in+Paracentrotus+lividus+(Lam)+and+Stylocidaris+affinis+(Phil)+(Echinodermata,+Echinoidea).">Mechanical properties of sea-urchin lantern muscles: a comparative investigation of intact muscle groups in Paracentrotus lividus (Lam) and Stylocidaris affinis (Phil) (Echinodermata, Echinoidea).</a> J. Comp. Physiol. B. 168 (3), 204-212 (1998).</li><li>Witze, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NASA+plans+Mars+sample-return+rover.">NASA plans Mars sample-return rover.</a> Nature. 509 (7500), 272 (2014).</li></ol>

Sea urchins use the Aristotle&#39;s lantern (Figure 1A) for a variety of functions (feeding, boring, pivoting, etc.). The fossil record indicates that the lantern has evolved in shape and function from the most primitive cidaroid type to the camarodont type of modern sea urchins14. Cidaroid lanterns have longitudinally grooved teeth (Figure 1B, top) and non-separated muscle attachment to its pyramid structure. This limits their up and down movement and robs them of th...

The fields of biology, biological materials science, biomaterials, bioengineering and biochemistry employ the premiere scientific techniques and minds in an attempt to provide a deeper understanding of the incredible natural world. This research has explained many of the most amazing biological structures and organisms; from the intrinsic toughness of human bone1,2 to the large beak of the toucan3. However, much of this knowledge is difficult to employ in a manner that can provide a benefit to society. As a result, the tangential field of bioinspiration employs the lessons learned from nature to modern materials in order to solve common problems. Examples include superhydrophobic surfaces inspired by lotus leaves4-6, adhesive surfaces inspired by the feet of geckos and insects7,8, tough ceramics inspired by the nacre of abalone9-11 and biopsy harvesters inspired by the mouthpiece of the sea urchin, also known as the Aristotle&#39;s lantern12,13.
Sea urchins are invertebrate animals covered with spines whose habitat most commonly consists of the rocky beds on the ocean floor. The body (called a test) in the largest urchin species can be more than 18 cm in diameter; test size in pink sea urchins (Strongylocentrotus fragilis) examined in this study can grow to 10 cm diameter. The Aristotle&#39;s lantern is composed of five predominately calcium carbonate teeth supported by pyramid structures composed of mineralized tissue and arranged into a dome-like formation that enclose all but the distal grinding tips of the teeth (Figure 1A).
The muscle structure of the jaws is capable of efficient chewing and scraping even against hard ocean rocks and corals. When the jaws open, the teeth protrude outwards and when the jaws close, the teeth retract inwards in a single smooth motion. Comparison between primitive (above) and modern (below) sea urchin tooth cross-sections (Figure 1B) indicates that a keeled tooth evolved to strengthen the tooth when grinding against hard substrates. Each individual tooth has a slightly convex curvature and a T-shaped morphology in the transverse plane (normal to the growth direction) due to the longitudinally attached keel (Figure 1C, D).
Bioinspiration begins with observation of interesting natural phenomena, such as the efficient chewing motion of the Aristotle&#39;s lantern in sea urchins. This natural structure initially captivated Aristotle because it reminded him of a horn lantern with the panes of horn left out. More than two millennia later, Scarpa was fascinated by the complexity of the Aristotle&#39;s lantern that he and later Trogu mimicked the natural chewing motion using only paper and rubber bands (Figure 2A)15,16. Similarly, Jelinek was bioinspired by the chewing motion of the Aristotle&#39;s lantern and developed a better biopsy harvester that could safely isolate tumorous tissue without spreading cancerous cells (Figure 2B, C)12,13. In this case, bioinspired design was utilized to make a biomedical device that fit a specific need for a desired application.
The design protocol described here applies to a sediment sampler bioinspired by sea urchins. Through biological materials science, the natural structure of the Aristotle&#39;s lantern is characterized. Bioinspired design identifies potential applications where the natural mechanisms can be enhanced through the use of modern materials and fabrication techniques. The final design is re-examined through the prism of bioexploration to understand how the natural tooth structure evolved (Figure 3). The last bioexploration step, proposed by Porter17,18, uses engineering analysis methods to explore and explain biological phenomena. All the important steps of the bioinspiration process are presented as an example for harnessing technology, pre-approved by nature, which can be used for solving modern problems. Our protocol, motivated by previous bioinspiration procedures presented for specific applications by Arzt7, is targeted for biologists, engineers and anyone else who is inspired by nature.

<table>
	<tbody>
		<tr>
			<td>BUEHLERMET II 8 PLN 600/P1200</td>
			<td>Buehler</td>
			<td>305308600102</td>
			<td>Abrasive paper for polishing</td>
		</tr>
		<tr>
			<td>TRIDENT POLISH CLOTH 8&#34; PSA</td>
			<td>Buehler</td>
			<td>407518</td>
			<td>Polish cloth for 3 um suspension</td>
		</tr>
		<tr>
			<td>METADI SUPREME POLY SUSP,3MIC&#160;</td>
			<td>Buehler</td>
			<td>406631</td>
			<td>Polish suspension (3 um)</td>
		</tr>
		<tr>
			<td>MICROCLOTH FOR 8 IN WHEEL PSA</td>
			<td>Buehler</td>
			<td>407218</td>
			<td>Polish cloth for 50 nm suspension</td>
		</tr>
		<tr>
			<td>MASTERPREP SUSPENSION, 6 OZ</td>
			<td>Buehler</td>
			<td>636377006</td>
			<td>Polish suspension (50 nm)</td>
		</tr>
		<tr>
			<td>Skyscan 1076 micro-CT Scanner</td>
			<td>Bruker</td>
			<td></td>
			<td>Micro-CT scanner equipment</td>
		</tr>
		<tr>
			<td>Amira software</td>
			<td>FEI Visualization Sciences Group</td>
			<td></td>
			<td>Software for 3D manipulation of Micro-CT scans</td>
		</tr>
		<tr>
			<td>FEI Philips XL30</td>
			<td>FEI Philips</td>
			<td></td>
			<td>ESEM equipment for characterization of polished tooth cross-sections</td>
		</tr>
		<tr>
			<td>SolidWorks Design software</td>
			<td>Dassault Systems</td>
			<td></td>
			<td>Design software for CAD drawing bioinspired device</td>
		</tr>
		<tr>
			<td>SolidWorks Simulation software</td>
			<td>Dassault Systems</td>
			<td></td>
			<td>Simulation software for stress test of CAD drawing bioinspired device</td>
		</tr>
		<tr>
			<td>Dimension 1200es</td>
			<td>Stratasys</td>
			<td></td>
			<td>3D printer for fabrication of bioinspired device from CAD drawing</td>
		</tr>
		<tr>
			<td>ABSplus</td>
			<td>Stratasys</td>
			<td></td>
			<td>3D printer plastic</td>
		</tr>
	</tbody>
</table>

a protocol for bioinspired design: a ground sampler based on sea urchin jaws

Bioinspired design is an emerging field that takes inspiration from nature to develop high-performance materials and devices. The sea urchin mouthpiece, known as the Aristotle's lantern, is a compelling source of bioinspiration with an intricate network of musculature and calcareous teeth that can scrape, cut, chew food and bore holes into rocky substrates. We describe the bioinspiration process as including animal observation, specimen characterization, device fabrication and mechanism bioexploration. The last step of bioexploration allows for a deeper understanding of the initial biology. The design architecture of the Aristotle's lantern is analyzed with micro-computed tomography and individual teeth are examined with scanning electron microscopy to identify the microstructure. Bioinspired designs are fabricated with a 3D printer, assembled and tested to determine the most efficient lantern opening and closing mechanism. Teeth from the bioinspired lantern design are bioexplored via finite element analysis to explain from a mechanical perspective why keeled tooth structures evolved in the modern sea urchins we observed. This circular approach allows for new conclusions to be drawn from biology and nature.

Bioinspired design of the Aristotle&#39;s lantern sampling device depends heavily upon the quality of the characterization methods used. Non-invasive techniques like &#181;-CT are helpful for analyzing the whole lantern and individual teeth to apply application specific enhancements for the bioinspired design (Figure 4). Meanwhile, the tooth microstructure can be explored via secondary electron and back-scattered electron micrographs of the polished cross-section of an in...

Watch this Scientific Journal Video about A Protocol for Bioinspired Design: A Ground Sampler Based on Sea Urchin Jaws at JoVE.com

A Protocol for Bioinspired Design: A Ground Sampler Based on Sea Urchin Jaws

A protocol for bioinspired design is described for a sampling device based on the jaws of a sea urchin. The bioinspiration process includes observing the sea urchins, characterizing the mouthpiece, 3D printing of the teeth and their assembly, and bioexploring the tooth structure.

Bioinspired design is an emerging field that takes inspiration from nature to develop high-performance materials and devices. The sea urchin mouthpiece, ...

The aim of this protocol is to examine the natural structure of the sea urchin mouthpiece, Aristotle's lantern, to develop a sediment sampling prototype using engineering analysis to test the application of biological features in bio-inspired designs. This method can help answer key questions in the bio-inspired design field. Specifically why did a keeled tooth structure evolve in sea urchins and how might it be useful for sediment sampling.The main advantage of this technique is that it provides a general framework for bio-inspired design investigations of various natural structures. Other such structures include the seahorse tail, the scutes of the boxfish, and the spines of the porcupine fish. The implications of this technically makes enhancement a proprietary surface expoloration because mineral poles are fit with bio-spar sediment samplers can efficiently collect a little samples.Generally individuals new to this method will struggle because objectives for each bio-inspired protocol will vary depending on the type of natural structure examined. After thawing the sea urchin, set it up for dissection with the tips of the teeth pointed up. And start cutting away the connective tissue around the perimeter of the Aristotle's lantern.Then, carefully lift out the lantern and rinse it off with running distilled water. Use forceps to remove remnant tissue on the outside and carefully open the lantern to extract the teeth. Alternatively, a dried lantern that is rinsed off again with water will fall apart to allow for easier access to the teeth.Now, pick up a tooth and carefully submerge it in a tube of freshly prepared epoxy. Position the curved concave side facing up and do not let the tooth touch the tube wall. Then, let the epoxy cure at room temperature for 24 hours.The next day, use a sectioning saw to remove the epoxy around the tooth down to about one cubic centimeter. Then, with a piece of coarse sandpaper number 125 or higher and using light pressure, rub the sample in one direction for five minutes. Progressively change to finer and finer grit sandpapers, up to the number 2400.For each sandpaper grit, make sure to rotate the sample 90 degrees. Use a microscope as needed to verify that the rubbing is always in the same direction for each sandpaper grit. After the sanding, moisten a microcloth with a 50 percent by volume half micron aluminina polish in water.Then rub the sample in a back and forth motion for five minutes. After polishing use particle-free tissue paper to clean off the sample, and then wrap it up in the same paper for storage. Next, characterize the tooth's microstructure using scanning electron microscopy.After applying a sputter coat, take 250 to 500x micrograph images of the sample. Next take microcomputed tomography scans of the whole pink sea urchin and the freshly dissected Aristotle's lantern. Place the samples over a moistened tissue when in the imaging chamber.For the body, scan with an isotropic voxel size of 36 microns at 100 peak kilovoltage and 100 milliamps. For the lantern, scan with an isotropic voxel size of about nine microns at 70 peak kilovoltage and 141 milliamps. Use a one point zero millimeter aluminum filter for both.Using micro CT scans and CAD modeling a bio-inspired design was produced with five curved teeth with a height of six centimeters and a diameter of eight centimeters for the closed lantern, which is five times larger than the natural Aristotle's lantern. For each component of the bio-inspired jaw produce STL files for 3D printing. Prepare the 3D printer by first loading acrylonitrile butadiene styrene plastic, and support plastic material cartridges.Then insert the modeling base onto the z platform by first aligning the tabs on the base with the slots in the tray. Now open the STL file parts and follow the display screen steps to orient and print individual lantern parts at the same time. Shown here is an example for 3D printing a joint arm.After printing the files, release the modeling base from the tabs and slide the base out of the printer along the tray guides. Then, use a metal spatula to pry the printed parts off the base. Once detached, place the printed parts into a heated base bath until the support plastic material dissolves.Now, fasten each tooth to a joint arm with a link rod using e-retaining rings on either side and assemble the bio-inspired Aristotle's lantern. Using the CAD file for the bio-inspired tooth perform a finite element modeling stress analysis test. First, open the file.Start a new study. And choose to run a static test with a fixed geometry. Then, click on the interfaces to add fixtures to the mounting holes where the pins will go.Next, set the force of the external loads. Click on the tooth grinding tip faces to apply a 45 Newton force to the edges. Now, set the gravity.Indicate in the top plane setting that the gravity force should be applied normally to the plane. Next, create a mesh on the design surface, and set the mesh density to fine. Now, run the test to compare between a tooth with and without the keel.A colored scale will show the areas of highest stress. Non-invasive imaging of the sea urchin tooth and the Aristotle's lantern were instrumental in producing a bio-inspired design. Detailed analysis of the tooth's microstructure by SEM confirmed the structural importance of the magnesium-enriched stone part in the tooth grinding tip.Plate and fiber primary elements are connected together by a matrix of secondary elements in the hardest stone region of the tooth grinding tip. The harder stone portion shown in darker gray, is composed of up to 40 percent magnesium atoms which replace the calcium atoms. Thus, the bio-inspired lantern was designed with CAD software, 3D printed and assembled.The ultimate purpose of the design is to collect sand. The importance of the keel in the design was tested using computerized stress tests on the CAD design. For 45 Newton applied force, the maximum stress experienced by the keeled tooth design was about 16 percent less.However, the keel adds only four percent to the mass of the design. When attempting a bio-inspired design protocol, it's important to start with careful observation of the natural structure in its living form, or through usage of non-invasive characterization methods, like micro CT and SEM. Following the general procedure, bio-inspired designs from other natural structures can be implemented in useful applications in a wide range of engineering fields.The final bio-exploration step based on the work of Professor Michael Porter, is especially essential for using engineering analysis methods to quantify the mechanical advantage of the keel structure in the sea urchin tooth.

a-protocol-for-bioinspired-design-ground-sampler-based-on-sea-urchin

Research

JoVE Journal

Bioengineering

10.9K visualizações.  University of California, San Diego. The aim of this protocol is to examine the natural structure of the sea urchin mouthpiece, Aristotle's lantern, to develop a sediment sampling prototype using engineering analysis to test the application of biological features in bio-inspired designs. This method can help answer key questions in the bio-inspired design field. Specifically why did a keeled tooth structure evolve in sea urchins and how might it be useful for sediment sampling.The main advantage of this technique is that ...