Editing Biomimetics (section)

=== Structural materials ===
There is a great need for new structural materials that are light weight but offer exceptional combinations of [[stiffness]], strength, and [[toughness]].

Such materials would need to be manufactured into bulk materials with complex shapes at high volume and low cost and would serve a variety of fields such as construction, transportation, energy storage and conversion.<ref>Bio-Synthetic Hybrid Materials and Bionanoparticles, Editors: Alexander Boker, Patrick van Rijn, Royal Society of Chemistry, Cambridge 2016, https://pubs.rsc.org/en/content/ebook/978-1-78262-210-9</ref> In a classic design problem, strength and toughness are more likely to be mutually exclusive, i.e., strong materials are brittle and tough materials are weak. However, natural materials with complex and hierarchical material gradients that span from [[Nanoscopic scale|nano]]- to macro-scales are both strong and tough. Generally, most natural materials utilize limited chemical components but complex material architectures that give rise to exceptional mechanical properties. Understanding the highly diverse and multi functional biological materials and discovering approaches to replicate such structures will lead to advanced and more efficient technologies. [[Bone]], [[nacre]] (abalone shell), teeth, the dactyl clubs of stomatopod shrimps and bamboo are great examples of damage tolerant materials.<ref name="materials">{{Cite journal|last1=Wegst|first1=Ulrike G. K.|last2=Bai|first2=Hao|last3=Saiz|first3=Eduardo|last4=Tomsia|first4=Antoni P.|last5=Ritchie|first5=Robert O.|date=2014-10-26|title=Bioinspired structural materials|journal=Nature Materials|volume=14|issue=1|pages=23–36|doi=10.1038/nmat4089|pmid=25344782|s2cid=1400303 |issn=1476-1122}}</ref> The exceptional resistance to [[fracture]] of bone is due to complex deformation and toughening mechanisms that operate at spanning different size scales &mdash; nanoscale structure of protein molecules to macroscopic physiological scale.<ref>{{Cite journal|last1=Launey|first1=Maximilien E.|last2=Buehler|first2=Markus J.|last3=Ritchie|first3=Robert O.|date=June 2010|title=On the Mechanistic Origins of Toughness in Bone|journal=[[Annual Review of Materials Research]]|volume=40|issue=1|pages=25–53|doi=10.1146/annurev-matsci-070909-104427|issn=1531-7331|citeseerx=10.1.1.208.4831|bibcode=2010AnRMS..40...25L|s2cid=6552812 }}</ref> [[File:Bruchfläche eines Perlmuttstücks.JPG|thumb|Electron microscopy image of a fractured surface of [[nacre]]|alt=]][[Nacre]] exhibits similar mechanical properties however with rather simpler structure. Nacre shows a brick and mortar like structure with thick mineral layer (0.2–0.9&nbsp;μm) of closely packed aragonite structures and thin organic matrix (~20&nbsp;nm).<ref>{{Cite journal|last1=Wang|first1=Rizhi|last2=Gupta|first2=Himadri S.|date=2011-08-04|title=Deformation and Fracture Mechanisms of Bone and Nacre|journal=[[Annual Review of Materials Research]]|volume=41|issue=1|pages=41–73|doi=10.1146/annurev-matsci-062910-095806|issn=1531-7331|bibcode=2011AnRMS..41...41W}}</ref> While thin films and micrometer sized samples that mimic these structures are already produced, successful production of bulk biomimetic structural materials is yet to be realized. However, numerous processing techniques have been proposed for producing nacre like materials.<ref name="materials" /> [[Pavement cells]], epidermal cells on the surface of plant leaves and petals, often form wavy interlocking patterns resembling jigsaw puzzle pieces and are shown to enhance the fracture toughness of leaves, key to plant survival.<ref name="auto1">{{cite journal |last1=Bidhendi|first1=Amir J. |last2=Lampron |first2=Olivier|last3=Gosselin|first3=Frédérick P. |last4=Geitmann |first4=Anja |title = Cell geometry regulates tissue fracture |journal=Nature Communications |date=December 2023 |volume=14 |issue=1 |pages=8275|doi=10.1038/s41467-023-44075-4|pmid=38092784 |pmc=10719271 |bibcode=2023NatCo..14.8275B }}</ref> Their pattern, replicated in laser-engraved [[Poly(methyl methacrylate)]] samples, was also demonstrated to lead to increased fracture toughness. It is suggested that the arrangement and patterning of cells play a role in managing crack propagation in tissues.<ref name="auto1"/>

[[Biomineralization|Biomorphic mineralization]] is a technique that produces materials with morphologies and structures resembling those of natural living organisms by using bio-structures as templates for mineralization. Compared to other methods of material production, biomorphic mineralization is facile, environmentally benign and economic.<ref name="Tong">Tong-Xiang, Suk-Kwun, Di Zhang. "Biomorphic Mineralization: From biology to materials." State Key Lab of Metal Matrix Composites. Shanghai: Shanghai Jiaotong University, n.d. 545-1000.</ref>

[[Freeze-casting|Freeze casting]] (ice templating), an inexpensive method to mimic natural layered structures, was employed by researchers at Lawrence Berkeley National Laboratory to create alumina-Al-Si and IT HAP-epoxy layered composites that match the mechanical properties of bone with an equivalent mineral/organic content.<ref>{{Cite journal|last1=Deville|first1=Sylvain|last2=Saiz|first2=Eduardo|last3=Nalla|first3=Ravi K.|last4=Tomsia|first4=Antoni P.|date=2006-01-27|title=Freezing as a Path to Build Complex Composites|journal=Science|volume=311|issue=5760|pages=515–518|doi=10.1126/science.1120937|issn=0036-8075|pmid=16439659|arxiv=1710.04167|bibcode=2006Sci...311..515D|s2cid=46118585}}</ref> Various further studies<ref>{{Cite journal|last1=Munch|first1=E.|last2=Launey|first2=M. E.|last3=Alsem|first3=D. H.|last4=Saiz|first4=E.|last5=Tomsia|first5=A. P.|last6=Ritchie|first6=R. O.|date=2008-12-05|title=Tough, Bio-Inspired Hybrid Materials|journal=Science|volume=322|issue=5907|pages=1516–1520|doi=10.1126/science.1164865|issn=0036-8075|pmid=19056979|bibcode=2008Sci...322.1516M|s2cid=17009263|url=https://digital.library.unt.edu/ark:/67531/metadc932916/}}</ref><ref>{{Cite journal|last1=Liu|first1=Qiang|last2=Ye|first2=Feng|last3=Gao|first3=Ye|last4=Liu|first4=Shichao|last5=Yang|first5=Haixia|last6=Zhou|first6=Zhiqiang|date=February 2014|title=Fabrication of a new SiC/2024Al co-continuous composite with lamellar microstructure and high mechanical properties|journal=Journal of Alloys and Compounds|volume=585|pages=146–153|doi=10.1016/j.jallcom.2013.09.140|issn=0925-8388}}</ref><ref>{{Cite journal|last1=Roy|first1=Siddhartha|last2=Butz|first2=Benjamin|last3=Wanner|first3=Alexander|date=April 2010|title=Damage evolution and domain-level anisotropy in metal/ceramic composites exhibiting lamellar microstructures|journal=Acta Materialia|volume=58|issue=7|pages=2300–2312|doi=10.1016/j.actamat.2009.12.015|bibcode=2010AcMat..58.2300R|issn=1359-6454}}</ref><ref>{{Cite journal|last1=Bouville|first1=Florian|last2=Maire|first2=Eric|last3=Meille|first3=Sylvain|last4=Van de Moortèle|first4=Bertrand|last5=Stevenson|first5=Adam J.|last6=Deville|first6=Sylvain|date=2014-03-23|title=Strong, tough and stiff bioinspired ceramics from brittle constituents|journal=Nature Materials|volume=13|issue=5|pages=508–514|doi=10.1038/nmat3915|pmid=24658117|issn=1476-1122|arxiv=1506.08979|bibcode=2014NatMa..13..508B|s2cid=205409702}}</ref> also employed similar methods to produce high strength and high toughness composites involving a variety of constituent phases.

Recent studies demonstrated production of cohesive and self supporting macroscopic tissue constructs that mimic [[Tissue (biology)|living tissues]] by printing tens of thousands of heterologous picoliter droplets in software-defined, 3D millimeter-scale geometries.<ref>{{Cite journal|last1=Villar|first1=Gabriel|last2=Graham|first2=Alexander D.|last3=Bayley|first3=Hagan|date=2013-04-05|title=A Tissue-Like Printed Material|journal=Science|volume=340|issue=6128|pages=48–52|doi=10.1126/science.1229495|issn=0036-8075|pmid=23559243|pmc=3750497|bibcode=2013Sci...340...48V}}</ref> Efforts are also taken up to mimic the design of nacre in artificial [[composite material]]s using fused deposition modelling<ref>{{Cite journal|last1=Espinosa|first1=Horacio D.|last2=Juster|first2=Allison L.|last3=Latourte|first3=Felix J.|last4=Loh|first4=Owen Y.|last5=Gregoire|first5=David|last6=Zavattieri|first6=Pablo D.|date=2011-02-01|title=Tablet-level origin of toughening in abalone shells and translation to synthetic composite materials|journal=Nature Communications|volume=2|issue=1|pages=173|doi=10.1038/ncomms1172|pmid=21285951|issn=2041-1723|bibcode=2011NatCo...2..173E|doi-access=free}}</ref> and the helicoidal structures of [[Mantis shrimp|stomatopod]] clubs in the fabrication of high performance [[Carbon fibers|carbon fiber]]-epoxy composites.<ref>{{Cite journal|date=2014-09-01|title=Bio-inspired impact-resistant composites|journal=Acta Biomaterialia|volume=10|issue=9|pages=3997–4008|doi=10.1016/j.actbio.2014.03.022|pmid=24681369|issn=1742-7061|last1=Grunenfelder|first1=L.K.|last2=Suksangpanya|first2=N.|last3=Salinas|first3=C.|last4=Milliron|first4=G.|last5=Yaraghi|first5=N.|last6=Herrera|first6=S.|last7=Evans-Lutterodt|first7=K.|last8=Nutt|first8=S.R.|last9=Zavattieri|first9=P.|last10=Kisailus|first10=D.}}</ref>

Various established and novel additive manufacturing technologies like PolyJet printing, direct ink writing, 3D magnetic printing, multi-material magnetically assisted 3D printing and magnetically assisted [[Slipcasting|slip casting]] have also been utilized to mimic the complex micro-scale architectures of natural materials and provide huge scope for future research.<ref>{{cite journal |last1=Das |first1=Ratul |last2=Ahmad |first2=Zain |last3=Nauruzbayeva |first3=Jamilya |last4=Mishra |first4=Himanshu |title=Biomimetic Coating-free Superomniphobicity |journal=Scientific Reports |date=13 May 2020 |volume=10 |issue=1 |pages=7934 |doi=10.1038/s41598-020-64345-1 |pmid=32404874 |language=en |issn=2045-2322|pmc=7221082 |bibcode=2020NatSR..10.7934D }}</ref><ref>{{Cite journal|last=Studart|first=André R.|s2cid=3218518|date=2016|title=Additive manufacturing of biologically-inspired materials|journal=Chemical Society Reviews|volume=45|issue=2|pages=359–376|doi=10.1039/c5cs00836k|pmid=26750617|issn=0306-0012}}</ref><ref>{{cite journal |last1=Islam |first1=Muhammed Kamrul |last2=Hazell |first2=Paul J. |last3=Escobedo |first3=Juan P. |last4=Wang |first4=Hongxu |title=Biomimetic armour design strategies for additive manufacturing: A review |journal=Materials & Design |date=July 2021 |volume=205 |pages=109730 |doi=10.1016/j.matdes.2021.109730 |doi-access=free }}</ref>

[[Spider]] silk is tougher than [[Kevlar]] used in [[Ballistic vest|bulletproof vests]].<ref>{{Cite journal|last1=Gu|first1=Yunqing|last2=Yu|first2=Lingzhi|last3=Mou|first3=Jiegang|last4=Wu|first4=Denghao|last5=Zhou|first5=Peijian|last6=Xu|first6=Maosen|date=2020-08-24|title=Mechanical properties and application analysis of spider silk bionic material|journal=E-Polymers|language=en|volume=20|issue=1|pages=443–457|doi=10.1515/epoly-2020-0049|s2cid=221372172|issn=2197-4586|doi-access=free}}</ref> Engineers could in principle use such a material, if it could be reengineered to have a long enough life, for parachute lines, suspension bridge cables, artificial ligaments for medicine, and other purposes.<ref name="Benyus 1997" /> The self-sharpening teeth of many animals have been copied to make better cutting tools.<ref>{{cite journal|last1=Killian|first1=Christopher E.|year=2010|title=Self-Sharpening Mechanism of the Sea Urchin Tooth|journal=Advanced Functional Materials|volume=21|issue=4|pages=682–690|doi=10.1002/adfm.201001546|s2cid=96221597 }}</ref>

New ceramics that exhibit giant electret hysteresis have also been realized.<ref>{{cite journal|last1=Yao|first1=Y.|last2=Wang|first2=Q.|last3=Wang|first3=H.|last4=Zhang|first4=B.|last5=Zhao|first5=C.|last6=Wang|first6=Z.|last7=Xu|first7=Z.|last8=Wu|first8=Y.|last9=Huang|first9=W.|year=2013|title=Bio-Assembled Nanocomposites in Conch Shells Exhibit Giant Electret Hysteresis|journal=Adv. Mater.|volume=25|issue=5|pages=711–718|doi=10.1002/adma.201202079|pmid=23090938|last10=Qian|first10=P.-Y.|last11=Zhang|first11=X. X.|bibcode=2013AdM....25..711Y |s2cid=205246425 }}</ref>