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Aziz S, Zhang X, Naficy S, Salahuddin B, Jager EWH, Zhu Z. Plant-Like Tropisms in Artificial Muscles. Advanced Materials 2023; 35:e2212046. [PMID: 36965152 DOI: 10.1002/adma.202212046] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/15/2023] [Indexed: 05/16/2023]
Abstract
Helical plants have the ability of tropisms to respond to natural stimuli, and biomimicry of such helical shapes into artificial muscles has been vastly popular. However, the shape-mimicked actuators only respond to artificially provided stimulus, they are not adaptive to variable natural conditions, thus being unsuitable for real-life applications where on-demand, autonomous operations are required. Novel artificial muscles made of hierarchically patterned helically wound yarns that are self-adaptive to environmental humidity and temperature changes are demonstrated here. Unlike shape-mimicked artificial muscles, a unique microstructural biomimicking approach is adopted, where the muscle yarns can effectively replicate the hydrotropism and thermotropism of helical plants to their microfibril level using plant-like microstructural memories. Large strokes, with rapid movement, are obtained when the individual microfilament of yarn is inlaid with hydrogel and further twisted into a coil-shaped hierarchical structure. The developed artificial muscle provides an average actuation speed of ≈5.2% s-1 at expansion and ≈3.1% s-1 at contraction cycles, being the fastest amongst previously demonstrated actuators of similar type. It is demonstrated that these muscle yarns can autonomously close a window in wet climates. The building block yarns are washable without any material degradation, making them suitable for smart, reusable textile and soft robotic devices.
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Affiliation(s)
- Shazed Aziz
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Xi Zhang
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Sina Naficy
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Bidita Salahuddin
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Edwin W H Jager
- Division of Sensor and Actuator Systems, Department of Physics, Chemistry, and, Biology (IFM), Linköping University, Linköping, SE-58183, Sweden
| | - Zhonghua Zhu
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, 4072, Australia
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2
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Choi M, Shin B, Kim HY. Hygromachines: Humidity-Powered Wheels, Seesaws, and Vehicles. Soft Robot 2023; 10:1171-1180. [PMID: 37339438 DOI: 10.1089/soro.2022.0218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2023] Open
Abstract
Hygroscopic soft actuators offer an attractive means to convert environmental energy to mechanical motions as they use water vapor, a ubiquitous substance in the atmosphere. To overcome the limits of existing hygroactuators, such as simplistic actuation mode, slow response, and low efficiency, here we present three kinds of humidity-powered soft machines adopting directionally electrospun hygroresponsive nanofibrous sheets. The wheels, seesaws, and vehicles developed in this work utilize spatial humidity gradient naturally established near moist surfaces such as human skin, so that they operate spontaneously, realizing energy scavenging or harvesting. We also constructed a theoretical framework to mechanically analyze their dynamics, which allowed us to optimize their design to obtain the highest motion speed physically possible.
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Affiliation(s)
- Munkyeong Choi
- Department of Mechanical Engineering, Seoul National University, Seoul, South Korea
| | - Beomjune Shin
- Department of Mechanical Engineering, Seoul National University, Seoul, South Korea
| | - Ho-Young Kim
- Department of Mechanical Engineering, Seoul National University, Seoul, South Korea
- Seoul National University, Institute of Advanced Machines and Design, Seoul, South Korea
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3
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Ohlendorf R, Tan NYH, Nakayama N. Engineering Themes in Plant Forms and Functions. Annu Rev Plant Biol 2023; 74:777-801. [PMID: 37216204 DOI: 10.1146/annurev-arplant-061422-094751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Living structures constantly interact with the biotic and abiotic environment by sensing and responding via specialized functional parts. In other words, biological bodies embody highly functional machines and actuators. What are the signatures of engineering mechanisms in biology? In this review, we connect the dots in the literature to seek engineering principles in plant structures. We identify three thematic motifs-bilayer actuator, slender-bodied functional surface, and self-similarity-and provide an overview of their structure-function relationships. Unlike human-engineered machines and actuators, biological counterparts may appear suboptimal in design, loosely complying with physical theories or engineering principles. We postulate what factors may influence the evolution of functional morphology and anatomy to dissect and comprehend better the why behind the biological forms.
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Affiliation(s)
- Rahel Ohlendorf
- Department of Bioengineering, Imperial College London, London, United Kingdom;
| | | | - Naomi Nakayama
- Department of Bioengineering, Imperial College London, London, United Kingdom;
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4
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Castro D, Aharoni H. Shape Morphing of Planar Liquid Crystal Elastomers. Phys Rev Lett 2023; 130:178101. [PMID: 37172258 DOI: 10.1103/physrevlett.130.178101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 03/17/2023] [Indexed: 05/14/2023]
Abstract
We consider planar liquid crystal elastomers: two-dimensional objects made of anisotropic responsive materials that remain flat when stimulated, however change their planar shape. We derive a closed form, analytical solution based on the implicit linearity featured by this subclass of deformations. Our solution provides the nematic director field on an arbitrary domain starting with two initial director curves. We discuss the different gauge choices for this problem and the inclusion of disclinations in the nematic order. Finally, we propose several applications and useful design principles based on this theoretical framework.
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Affiliation(s)
- Daniel Castro
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hillel Aharoni
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
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5
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Cecchini L, Mariani S, Ronzan M, Mondini A, Pugno NM, Mazzolai B. 4D Printing of Humidity-Driven Seed Inspired Soft Robots. Adv Sci (Weinh) 2023; 10:e2205146. [PMID: 36725304 PMCID: PMC10037692 DOI: 10.1002/advs.202205146] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/05/2022] [Indexed: 06/18/2023]
Abstract
Geraniaceae seeds represent a role model in soft robotics thanks to their ability to move autonomously across and into the soil driven by humidity changes. The secret behind their mobility and adaptivity is embodied in the hierarchical structures and anatomical features of the biological hygroscopic tissues, geometrically designed to be selectively responsive to environmental humidity. Following a bioinspired approach, the internal structure and biomechanics of Pelargonium appendiculatum (L.f.) Willd seeds are investigated to develop a model for the design of a soft robot. The authors exploit the re-shaping ability of 4D printed materials to fabricate a seed-like soft robot, according to the natural specifications and model, and using biodegradable and hygroscopic polymers. The robot mimics the movement and performances of the natural seed, reaching a torque value of ≈30 µN m, an extensional force of ≈2.5 mN and it is capable to lift ≈100 times its own weight. Driven by environmental humidity changes, the artificial seed is able to explore a sample soil, adapting its morphology to interact with soil roughness and cracks.
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Affiliation(s)
- Luca Cecchini
- Bioinspired Soft Robotics LaboratoryIstituto Italiano di TecnologiaVia Morego 30Genova16163Italy
- Laboratory for BioinspiredBionicNanoMeta Materials and MechanicsDepartment of CivilEnvironmental and Mechanical EngineeringUniversity di TrentoVia Mesiano 77Trento38123Italy
| | - Stefano Mariani
- Bioinspired Soft Robotics LaboratoryIstituto Italiano di TecnologiaVia Morego 30Genova16163Italy
| | - Marilena Ronzan
- Bioinspired Soft Robotics LaboratoryIstituto Italiano di TecnologiaVia Morego 30Genova16163Italy
| | - Alessio Mondini
- Bioinspired Soft Robotics LaboratoryIstituto Italiano di TecnologiaVia Morego 30Genova16163Italy
| | - Nicola M. Pugno
- Laboratory for BioinspiredBionicNanoMeta Materials and MechanicsDepartment of CivilEnvironmental and Mechanical EngineeringUniversity di TrentoVia Mesiano 77Trento38123Italy
- School of Engineering and Materials ScienceQueen Mary University of LondonMile End RoadLondonE1 4NSUK
| | - Barbara Mazzolai
- Bioinspired Soft Robotics LaboratoryIstituto Italiano di TecnologiaVia Morego 30Genova16163Italy
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6
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Luo D, Maheshwari A, Danielescu A, Li J, Yang Y, Tao Y, Sun L, Patel DK, Wang G, Yang S, Zhang T, Yao L. Autonomous self-burying seed carriers for aerial seeding. Nature 2023; 614:463-470. [PMID: 36792743 DOI: 10.1038/s41586-022-05656-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 12/14/2022] [Indexed: 02/17/2023]
Abstract
Aerial seeding can quickly cover large and physically inaccessible areas1 to improve soil quality and scavenge residual nitrogen in agriculture2, and for postfire reforestation3-5 and wildland restoration6,7. However, it suffers from low germination rates, due to the direct exposure of unburied seeds to harsh sunlight, wind and granivorous birds, as well as undesirable air humidity and temperature1,8,9. Here, inspired by Erodium seeds10-14, we design and fabricate self-drilling seed carriers, turning wood veneer into highly stiff (about 4.9 GPa when dry, and about 1.3 GPa when wet) and hygromorphic bending or coiling actuators with an extremely large bending curvature (1,854 m-1), 45 times larger than the values in the literature15-18. Our three-tailed carrier has an 80% drilling success rate on flat land after two triggering cycles, due to the beneficial resting angle (25°-30°) of its tail anchoring, whereas the natural Erodium seed's success rate is 0%. Our carriers can carry payloads of various sizes and contents including biofertilizers and plant seeds as large as those of whitebark pine, which are about 11 mm in length and about 72 mg. We compare data from experiments and numerical simulation to elucidate the curvature transformation and actuation mechanisms to guide the design and optimization of the seed carriers. Our system will improve the effectiveness of aerial seeding to relieve agricultural and environmental stresses, and has potential applications in energy harvesting, soft robotics and sustainable buildings.
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Affiliation(s)
- Danli Luo
- Morphing Matter Lab, Human-Computer Interaction Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | | | | | - Jiaji Li
- College of Computer Science and Technology, Zhejiang University, Hangzhou, China
| | - Yue Yang
- College of Computer Science and Technology, Zhejiang University, Hangzhou, China
| | - Ye Tao
- School of Art and Archeology, Zhejiang University City College, Hangzhou, China
| | - Lingyun Sun
- College of Computer Science and Technology, Zhejiang University, Hangzhou, China
| | - Dinesh K Patel
- Morphing Matter Lab, Human-Computer Interaction Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Guanyun Wang
- Morphing Matter Lab, Human-Computer Interaction Institute, Carnegie Mellon University, Pittsburgh, PA, USA.
- College of Computer Science and Technology, Zhejiang University, Hangzhou, China.
| | - Shu Yang
- Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, USA.
| | - Teng Zhang
- Department of Mechanical and Aerospace Engineering, Syracuse University, Syracuse, NY, USA.
- BioInspired Syracuse, Syracuse University, Syracuse, NY, USA.
| | - Lining Yao
- Morphing Matter Lab, Human-Computer Interaction Institute, Carnegie Mellon University, Pittsburgh, PA, USA.
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7
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Li Q, Jiao Y. Ultrafast Photothermal Actuators with a Large Helical Curvature Based on Ultrathin GO and Biaxially Oriented PE Films. ACS Appl Mater Interfaces 2022; 14:55828-55838. [PMID: 36484521 DOI: 10.1021/acsami.2c18478] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In nature, there are some amazing superfast actuations (Venus flytrap) and large-curvature helical deformations (the awn of Erodium). Although many bionic actuators have been made (electrothermal, hygroscopic, photoinduced), most of their actuations are slow and small, not comparable to the wonderful ones in nature. Here, we report an ultrafast photothermal actuator with large-curvature curling based on an ultrathin graphene oxide (GO) and biaxially oriented polyethylene (BOPE) bilayer film (thickness ∼11 μm). By virtue of the fast temperature changing rate (peak: 900 °C s-1 during infrared heating and -1200 °C s-1 during cooling) and the great difference in the coefficient of thermal expansion of GO and BOPE layers, the actuator deforms rapidly and greatly. The maximum bending speed and curvature can reach 5300° s-1 and 22 cm-1, respectively, which are comparable to those of wonderful natural actuators and far exceed the performances of the reported artificial actuators. Different from ordinary helical actuators made of uniaxial anisotropic materials, our actuator is based on a typical biaxial anisotropic material of BOPE. However, the morphing behaviors of this type of actuator have not been reported before. So for the first time, we systematically studied this problem through experiments and simulations using the GO-BOPE actuator as a prototype and have drawn clear conclusions. In addition, functional GO-BOPE actuators capable of winding around and manipulating tiny objects were also designed and developed. We think this ultrafast large-curvature photothermal actuator will have wide application prospects in bionic actuations and dexterous robots.
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Affiliation(s)
- Qingwei Li
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing100081, China
| | - Yan Jiao
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing100081, China
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8
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Zhang F, Yang M, Xu X, Liu X, Liu H, Jiang L, Wang S. Unperceivable motion mimicking hygroscopic geometric reshaping of pine cones. Nat Mater 2022; 21:1357-1365. [PMID: 36357689 DOI: 10.1038/s41563-022-01391-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 09/28/2022] [Indexed: 06/16/2023]
Abstract
The hygroscopic deformation of pine cones, featured by opening and closing their scales depending on the environmental humidity, is a well-known stimuli-responsive model system for artificial actuators. However, it has not been noted that the deformation of pine cones is an ultra-slow process. Here, we reveal that vascular bundles with unique parallelly arranged spring/square microtubular heterostructures dominate the hygroscopic movement, characterized as ultra-slow motion with the outer sclereids. The spring microtubes give a much larger hygroscopic deformation than that of the square microtubes along the longitudinal axis direction, which bends the vascular bundles and consequently drives the scales to move. The outer sclereids with good water retention enable the vascular-bundle-triggered deformation to proceed ultra-slowly. Drawing inspiration, we developed soft actuators enabling controllable yet unperceivable motion. The motion velocity is almost two orders of magnitude lower than that of the same-class actuators reported, which made the as-developed soft actuators applicable in camouflage and reconnaissance.
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Affiliation(s)
- Feilong Zhang
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, CAS Center for Excellence in Nanoscience, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, P. R. China
| | - Man Yang
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, CAS Center for Excellence in Nanoscience, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, P. R. China
| | - Xuetao Xu
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, CAS Center for Excellence in Nanoscience, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, P. R. China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Xi Liu
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, CAS Center for Excellence in Nanoscience, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, P. R. China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Huan Liu
- Research Institute for Frontier Science, Beihang University, Beijing, P. R. China.
| | - Lei Jiang
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, CAS Center for Excellence in Nanoscience, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, P. R. China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, P. R. China
- Research Institute for Frontier Science, Beihang University, Beijing, P. R. China
| | - Shutao Wang
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, CAS Center for Excellence in Nanoscience, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, P. R. China.
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, P. R. China.
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9
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Zhang Y, Zhang C, Wang R, Tan W, Gu Y, Yu X, Zhu L, Liu L. Development and challenges of smart actuators based on water-responsive materials. Soft Matter 2022; 18:5725-5741. [PMID: 35904079 DOI: 10.1039/d2sm00519k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Water-responsive (WR) materials, due to their controllable mechanical response to humidity without energy actuation, have attracted lots of attention to the development of smart actuators. WR material-based smart actuators can transform natural humidity to a required mechanical motion and have been widely used in various fields, such as soft robots, micro-generators, smart building materials, and textiles. In this paper, the development of smart actuators based on different WR materials has been reviewed systematically. First, the properties of different biological WR materials and the corresponding actuators are summarized, including plant materials, animal materials, and microorganism materials. Additionally, various synthetic WR materials and their related applications in smart actuators have also been introduced in detail, including hydrophilic polymers, graphene oxide, carbon nanotubes, and other synthetic materials. Finally, the challenges of the WR actuator are analyzed from the three perspectives of actuator design, control methods, and compatibility, and the potential solutions are also discussed. This paper may be useful for the development of not only soft actuators that are based on WR materials, but also smart materials applied to renewable energy.
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Affiliation(s)
- Yiwei Zhang
- School of Automation and Electrical Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning, China.
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
| | - Chuang Zhang
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
| | - Ruiqian Wang
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjun Tan
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanyu Gu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, 110819, China
| | - Xiaobin Yu
- School of Automation and Electrical Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning, China.
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
| | - Lizhong Zhu
- School of Automation and Electrical Engineering, Shenyang Ligong University, Shenyang 110159, Liaoning, China.
| | - Lianqing Liu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China.
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
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10
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Lindtner T, Uzan AY, Eder M, Bar-On B, Elbaum R. Repetitive hygroscopic snapping movements in awns of wild oats. Acta Biomater 2021; 135:483-492. [PMID: 34506974 DOI: 10.1016/j.actbio.2021.08.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/05/2021] [Accepted: 08/27/2021] [Indexed: 11/17/2022]
Abstract
Wild oat (Avena sterilis) is a very common annual plant species. Successful seed dispersion support its wide distribution in Africa, Asia and Europe. The seed dispersal units are made of two elongated stiff awns that are attached to a pointy compartment containing two seeds. The awns bend and twist with changes in humidity, pushing the seeds along and into the soil. The present work reveals the material structure of the awns, and models their functionality as two-link robotic arms. Based on nano-to-micro structure analyses the bending and twisting hygroscopic movements are explained. The coordinated movements of two sister awns attached to one dispersal unit were followed. Our work shows that sister awns intersect typically twice every wetting-drying cycle. Once the awns cross each other, epidermal silica hairs are suggested to lock subsequent movements, resulting in stress accumulation. Sudden release of the interlocked awns induces jumps of the dispersal unit and changes in its movement direction. Our findings propose a new role to epidermis silica hairs and a new facet of wild oat seed dispersion. Reversible jumping mechanism in multiple-awn seed dispersal units may serve as a blueprint for reversibly jumping robotic systems. STATEMENT OF SIGNIFICANCE: The seed dispersal unit of wild oats carries two elongated stiff awns covered by unidirectional silica hairs. The awns bend and twist with changes in humidity, pushing the seed capsule along and into the ground. We studied structures constructing the movement mechanism and modeled the awn as a two-link robotic arm. We show that sister awns, attached to the same seed capsule, intersect twice every drying cycle. Once the awns cross each other, the epidermal silica hairs are suggested to lock any subsequent movements, causing stress accumulation. Sudden release of the interlocked awns may cause the dispersal unit to jump and change its direction. Our findings suggest a new role to silica hairs and a new dispersal mechanism in multiple-awn seed dispersal units.
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Affiliation(s)
- Tom Lindtner
- School of Analytical Sciences Adlershof (SALSA), Humboldt-Universität zu Berlin, Albert-Einstein-Straße 5-9, 12489, Berlin-Adlershof, Germany; Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor-Str. 2, 12489, Berlin-Adlershof, Germany; The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, 7610001 Rehovot, Israel
| | - Avihai Yosef Uzan
- Department of Mechanical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Michaela Eder
- Max-Planck-Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Benny Bar-On
- Department of Mechanical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Rivka Elbaum
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, 7610001 Rehovot, Israel.
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11
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Zhao Z, Kumar J, Hwang Y, Deng J, Ibrahim MSB, Huang C, Suresh S, Cho NJ. Digital printing of shape-morphing natural materials. Proc Natl Acad Sci U S A 2021; 118:e2113715118. [PMID: 34663733 DOI: 10.1073/pnas.2113715118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2021] [Indexed: 12/16/2022] Open
Abstract
We demonstrate how programmable shape evolution and deformation can be induced in plant-based natural materials through standard digital printing technologies. With nonallergenic pollen paper as the substrate material, we show how specific geometrical features and architectures can be custom designed through digital printing of patterns to modulate hygrophobicity, geometry, and complex shapes. These autonomously hygromorphing configurations can be "frozen" by postprocessing coatings to meet the needs of a wide spectrum of uses and applications. Through computational simulations involving the finite element method and accompanying experiments, we develop quantitative insights and a general framework for creating complex shapes in eco-friendly natural materials with potential sustainable applications for scalable manufacturing.
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12
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Quan H, Pirosa A, Yang W, Ritchie RO, Meyers MA. Hydration-induced reversible deformation of the pine cone. Acta Biomater 2021; 128:370-383. [PMID: 33964479 DOI: 10.1016/j.actbio.2021.04.049] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 11/28/2022]
Abstract
The scales of pine cones undergo reversible deformation due to hydration changes in order to optimize seed dispersal. This improves the survivability of the pine. The reversible flexing of the scales is caused by two tissue layers arranged in a sandwich configuration: a layer composed of sclereid cells and a sclerenchyma layer. They expand differentially upon hydration (and contract upon dehydration) due to differences in the structure that are analyzed here for Torrey pine (Pinustorreyana) cones. In addition to this well-known mechanism by which the cellulose microfibrils in the scales vary their angle with the wood cell axis, we confirm the presence of a porosity gradient in the sclereid cells and calculate, using a model consisting of three layers, the stresses generated upon dehydration taking into account the effect of hydration on the elastic modulus. Our quantitative analysis reveals that this gradient structure can significantly decrease the stress concentrations due to the mismatch between the two layers, and show that this is an ingenious design to increase the interfacial toughness to improve the robustness of pine cone scales. We also show that each individual layer of sclereid cells and sclerenchyma fibers undergoes bending when hydrated separately, and suggest that the two layers operate synergistically to effect the required deformation for seed release. A synthetic bioinspired analog consisting of hydrogels with different porosities is used to confirm this principal actuation mechanism. These findings may inspire the materials science and mechanical engineering communities to develop more robust, biocompatible and energy-efficient actuation systems. STATEMENT OF SIGNIFICANCE: Some biological structures can exhibit reversible deformation enabled by water inflow and outflow of their structure. We analyse the reversible motion of pine cone scales. The dehydration produces their flexure and opening, resulting in the release of seeds and their dispersal, when conditions are right. This process is reversible, and rehydration of the pine cone recloses the scales. The processes of flexing and straightening are governed by shrinking and swelling which are directed by differences in the arrangement of cellulose microfibrils in a bilayer construct. We demonstrate that the scales are more complex than a simple bilayer structure and that they actually have gradients, which significantly reduce the internal stresses and ensure their integrity. We analyse the process of opening and closing of the scales for a gradient structure in the Torrey pine cone using a simple idealized trilayer model. The results demonstrate a significant decrease in internal stresses produced by the gradient structure. Using the lessons learned from the pine cone, we produce a bilayer junction using hydrogels with different porosities which exhibit the same reversible bending response.
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Affiliation(s)
- Haocheng Quan
- Materials Science and Engineering Program, University of California, San Diego, California 92093, USA
| | - Arnaud Pirosa
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093, USA
| | - Wen Yang
- Department of NanoEngineering, University of California, San Diego, California 92093, USA.
| | - Robert O Ritchie
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Marc A Meyers
- Materials Science and Engineering Program, University of California, San Diego, California 92093, USA; Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093, USA; Department of NanoEngineering, University of California, San Diego, California 92093, USA.
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13
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Abstract
Wood is a prototypical biological material, which adapts to mechanical requirements. The microarchitecture of cellulose fibrils determines the mechanical properties of woody materials, as well as their actuation properties, based on absorption and desorption of water. Herein it is argued that cellulose fiber orientation corresponds to an analog code that determines the response of wood to humidity as an active material. Examples for the harvesting of wood activity, as well as bioinspiration, are given.
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Affiliation(s)
- Michaela Eder
- Max-Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, Potsdam, 14476, Germany
| | - Wolfgang Schäffner
- Institute of Cultural History and Theory, Humboldt Universität zu Berlin, Berlin, 10117, Germany
| | - Ingo Burgert
- ETH Zürich, Wood Materials Science, Zürich, 8093, Switzerland
- Empa, Cellulose & Wood Materials Laboratory, Dübendorf, 8600, Switzerland
| | - Peter Fratzl
- Max-Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, Potsdam, 14476, Germany
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14
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Poppinga S, Schenck P, Speck O, Speck T, Bruchmann B, Masselter T. Self-Actuated Paper and Wood Models: Low-Cost Handcrafted Biomimetic Compliant Systems for Research and Teaching. Biomimetics (Basel) 2021; 6:biomimetics6030042. [PMID: 34206585 PMCID: PMC8293091 DOI: 10.3390/biomimetics6030042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/08/2021] [Accepted: 06/18/2021] [Indexed: 11/16/2022] Open
Abstract
The abstraction and implementation of plant movement principles into biomimetic compliant systems are of increasing interest for technical applications, e.g., in architecture, medicine, and soft robotics. Within the respective research and development approaches, advanced methods such as 4D printing or 3D-braiding pultrusion are typically used to generate proof-of-concept demonstrators at the laboratory or demonstrator scale. However, such techniques are generally time-consuming, complicated, and cost-intensive, which often impede the rapid realization of a sufficient number of demonstrators for testing or teaching. Therefore, we have produced comparable simple handcrafted compliant systems based on paper, wood, plastic foil, and/or glue as construction materials. A variety of complex plant movement principles have been transferred into these low-cost physical demonstrators, which are self-actuated by shrinking processes induced by the anisotropic hygroscopic properties of wood or paper. The developed systems have a high potential for fast, precise, and low-cost abstraction and transfer processes in biomimetic approaches and for the "hands-on understanding" of plant movements in applied university and school courses.
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Affiliation(s)
- Simon Poppinga
- Plant Biomechanics Group @ Botanic Garden, University of Freiburg, 79104 Freiburg im Breisgau, Germany; (P.S.); (O.S.); (T.S.)
- Freiburg Materials Research Center (FMF), University of Freiburg, 79104 Freiburg im Breisgau, Germany
- Cluster of Excellence livMatS @ FIT—Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79110 Freiburg im Breisgau, Germany
- Correspondence: (S.P.); (T.M.)
| | - Pablo Schenck
- Plant Biomechanics Group @ Botanic Garden, University of Freiburg, 79104 Freiburg im Breisgau, Germany; (P.S.); (O.S.); (T.S.)
| | - Olga Speck
- Plant Biomechanics Group @ Botanic Garden, University of Freiburg, 79104 Freiburg im Breisgau, Germany; (P.S.); (O.S.); (T.S.)
- Cluster of Excellence livMatS @ FIT—Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79110 Freiburg im Breisgau, Germany
| | - Thomas Speck
- Plant Biomechanics Group @ Botanic Garden, University of Freiburg, 79104 Freiburg im Breisgau, Germany; (P.S.); (O.S.); (T.S.)
- Freiburg Materials Research Center (FMF), University of Freiburg, 79104 Freiburg im Breisgau, Germany
- Cluster of Excellence livMatS @ FIT—Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79110 Freiburg im Breisgau, Germany
| | - Bernd Bruchmann
- BASF SE, Advanced Materials and Systems Research, 67056 Ludwigshafen/Rhein, Germany;
| | - Tom Masselter
- Plant Biomechanics Group @ Botanic Garden, University of Freiburg, 79104 Freiburg im Breisgau, Germany; (P.S.); (O.S.); (T.S.)
- Correspondence: (S.P.); (T.M.)
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15
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Xu Z, Zhou Y, Zhang B, Zhang C, Wang J, Wang Z. Recent Progress on Plant-Inspired Soft Robotics with Hydrogel Building Blocks: Fabrication, Actuation and Application. Micromachines (Basel) 2021; 12:608. [PMID: 34074051 DOI: 10.3390/mi12060608] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/19/2021] [Accepted: 05/19/2021] [Indexed: 01/22/2023]
Abstract
Millions of years’ evolution has imparted life on earth with excellent environment adaptability. Of particular interest to scientists are some plants capable of macroscopically and reversibly altering their morphological and mechanical properties in response to external stimuli from the surrounding environment. These intriguing natural phenomena and underlying actuation mechanisms have provided important design guidance and principles for man-made soft robotic systems. Constructing bio-inspired soft robotic systems with effective actuation requires the efficient supply of mechanical energy generated from external inputs, such as temperature, light, and electricity. By combining bio-inspired designs with stimuli-responsive materials, various intelligent soft robotic systems that demonstrate promising and exciting results have been developed. As one of the building materials for soft robotics, hydrogels are gaining increasing attention owing to their advantageous properties, such as ultra-tunable modulus, high compliance, varying stimuli-responsiveness, good biocompatibility, and high transparency. In this review article, we summarize the recent progress on plant-inspired soft robotics assembled by stimuli-responsive hydrogels with a particular focus on their actuation mechanisms, fabrication, and application. Meanwhile, some critical challenges and problems associated with current hydrogel-based soft robotics are briefly introduced, and possible solutions are proposed. We expect that this review would provide elementary tutorial guidelines to audiences who are interested in the study on nature-inspired soft robotics, especially hydrogel-based intelligent soft robotic systems.
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16
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Chakraborty J, Luo J, Dyson RJ. Lockhart with a twist: Modelling cellulose microfibril deposition and reorientation reveals twisting plant cell growth mechanisms. J Theor Biol 2021; 525:110736. [PMID: 33915144 DOI: 10.1016/j.jtbi.2021.110736] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 11/26/2020] [Accepted: 04/16/2021] [Indexed: 10/21/2022]
Abstract
Plant morphology emerges from cellular growth and structure. The turgor-driven diffuse growth of a cell can be highly anisotropic: significant longitudinally and negligible radially. Such anisotropy is ensured by cellulose microfibrils (CMF) reinforcing the cell wall in the hoop direction. To maintain the cell's integrity during growth, new wall material including CMF must be continually deposited. We develop a mathematical model representing the cell as a cylindrical pressure vessel and the cell wall as a fibre-reinforced viscous sheet, explicitly including the mechano-sensitive angle of CMF deposition. The model incorporates interactions between turgor, external forces, CMF reorientation during wall extension, and matrix stiffening. Using the model, we reinterpret some recent experimental findings, and reexamine the popular hypothesis of CMF/microtubule alignment. We explore how the handedness of twisting cell growth depends on external torque and intrinsic wall properties, and find that cells twist left-handedly 'by default' in some suitable sense. Overall, this study provides a unified mechanical framework for understanding left- and right-handed twist-growth as seen in many plants.
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Affiliation(s)
- Jeevanjyoti Chakraborty
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK; Mechanical Engineering Department, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India.
| | - Jingxi Luo
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK.
| | - Rosemary J Dyson
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK.
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17
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Abstract
This study examines the coiling and uncoiling motions of a soft pneumatic actuator inspired by the awn tissue of Erodium cicutarium. These tissues have embedded cellulose fibers distributed in a tilted helical pattern, which induces hygroscopic coiling and uncoiling in response to the daily changes in ambient humidity. Such sophisticated motions can eventually “drill” the seed at the tip of awn tissue into the soil: a drill bit in the plant kingdom. Through finite element simulation and experimental testing, this study examines a soft pneumatic actuator that has a similar reinforcing fiber layout to the Erodium plant tissue. This actuator, in essence, is a thin-walled elastomeric cylinder covered by tilted helical Kevlar fibers. Upon internal pressurization, it can exhibit a coiling motion by a combination of simultaneous twisting, bending, and extension. Parametric analyses show that the coiling motion characteristics are directly related to the geometry of tilted helical fibers. Notably, a moderate tilt in the reinforcing helical fiber leads to many coils of small radius, while a significant tilt gives fewer coils of larger radius. The results of this study can offer guidelines for constructing plant-inspired robotic manipulators that can achieve complicated motions with simple designs.
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Affiliation(s)
- Ryan Geer
- Department of Mechanical Engineering, Clemson University, Clemson, SC, United States
| | - Steven Iannucci
- Department of Mechanical Engineering, Clemson University, Clemson, SC, United States
| | - Suyi Li
- Department of Mechanical Engineering, Clemson University, Clemson, SC, United States
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18
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Li Q, Wang X, Dong L, Liu C, Fan S. Spirally deformable soft actuators and their designable helical actuations based on a highly oriented carbon nanotube film. Soft Matter 2019; 15:9788-9796. [PMID: 31746933 DOI: 10.1039/c9sm01966a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Spiral configurations and helical curlings of plant tendrils and seed pods are very common in nature. Many researchers have tried to develop spirally deformable actuators to mimic these natural spirals through several approaches, such as preforming helical shapes, processing diagonal stripes and employing anisotropic organic layers. However, these methods are usually complex and time-consuming. Here, we used an efficient method to produce a highly oriented carbon nanotube (CNT) film and develop a series of spirally deformable soft actuators which perform various controllable helical actuations. The actuator consists of a CNT layer with strong anisotropy and a silicone layer. By simply adjusting the orientations of the aligned CNTs, the prepared actuators can accomplish left- or right-handed spiral deformations with different helical forms when driven by electricity. Finite element analyses and simulations were conducted to investigate the mechanism. It is confirmed that it is the anisotropic moduli of the CNT film that regulate the internal stress distributions of the actuators and lead to helical actuations. Moreover, complex actuator designs and functional applications were also carried out. A V-shaped actuator can simultaneously achieve left- and right-handed curling with large angles (630°), which vividly imitates the spiral winding of a tendril. A Y-shaped actuator performed three-dimensional movements, which can manipulate lightweight objects deftly. By virtue of easy preparation and flexible function design, the spirally deformable actuators based on the oriented CNT film will be very promising in artificial muscles and bionic soft robots.
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Affiliation(s)
- Qingwei Li
- Intelligent Robotics Institute, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China.
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19
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Zhang P, Chen PY, Wang B, Yu R, Pan H, Wang B. Evaluating the hierarchical, hygroscopic deformation of the Daucus carota umbel through structural characterization and mechanical analysis. Acta Biomater 2019; 99:457-468. [PMID: 31525536 DOI: 10.1016/j.actbio.2019.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 12/27/2022]
Abstract
Many physically immobile plants develop passive yet ingenious strategies for active seed dispersal through self-deformation in response to external stimuli, such as humidity. These hygroscopic deformations are usually driven by the internal heterogeneous architecture, which provides valuable, inspiring information for the development of novel actuating systems. The Daucus carota compound umbel is an interesting structure showing a distinct hygroscopic deformation that operates at hierarchical levels among these plants. Here, we investigate the structure of the primary and secondary rays of the umbel associated with their deformation through mechanical analyses. We reveal that through controlling both the cellulose microfibril angle (MFA) and lignification, the multi-level bending behavior of the umbel is achieved, which contributes to efficient seed protection and dispersal. The primary rays generally show more significant bending curvature changes than the secondary rays, and within each level, the outer rays exhibit a larger motion amplitude than the middle and inner rays. Mechanical testing and theoretical analysis support that adjusting the lignin content within the ray structure compensates for the effect of the small differences in cellulose MFA on its bending behavior, which contributes to the overall hygroscopic deformation. Findings also show that the primary outer ray can generate reaction forces that are more than 700 times its weight, which is higher than that for the pine cone scales. The new insights from this work are instructive for bioinspired designs of complex, self-deforming structures and devices. STATEMENT OF SIGNIFICANCE: The carrot (Daucus carota) compound umbels exhibit a unique hierarchical, hygroscopic deformation for seed dispersal among immobile plants. In this work, we elucidate that the multi-level bending behavior of the umbel is achieved through manipulating the cellulose microfibril angle (MFA) and lignification of the primary and secondary rays for the first time. We also discover that adjusting the degree of lignification compensates for the effect of small cellulose MFA differences on the bending behavior theoretically and experimentally. The primary outer rays deform in a highly efficient manner, in which reactions forces about more than 700 times its weight are generated. The findings presented are instructive for bioinspired designs of complex, self-deforming structures and devices.
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20
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Almeida APC, Querciagrossa L, Silva PES, Gonçalves F, Canejo JP, Almeida PL, Godinho MH, Zannoni C. Reversible water driven chirality inversion in cellulose-based helices isolated from Erodium awns. Soft Matter 2019; 15:2838-2847. [PMID: 30869683 DOI: 10.1039/c8sm02290a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Among the movements observed in some cellulosic structures produced by plants are those that involve the dispersion and burial of seeds, as for example in Erodium from the Geraniaceae plant family. Here we report on a simple and efficient strategy to isolate and tune cellulose-based hygroscopic responsive materials from Erodium awns' dead tissues. The stimuli-responsive material isolated forms left-handed (L) or right-handed (R) helical birefringent transparent ribbons in the wet state that reversibly change to R helices when the material dries. The humidity-driven motion of dead tissues is most likely due to a composite material made of cellulose networks of fibrils imprinted by the plant at the nanoscale, which reinforces a soft wall polysaccharide matrix. The inversion of the handedness is explained using computational simulations considering filaments that contract and expand asymmetrically. The awns of Erodium are known to present hygroscopic movements, forming R helices in the dry state, but the possibility of actuating chirality via humidity suggests that these cellulose-based skeletons, which do not require complicated lithography and intricate deposition techniques, provide a diverse range of applications from intelligent textiles to micro-machines.
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Affiliation(s)
- Ana P C Almeida
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
| | - Lara Querciagrossa
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy.
| | - Pedro E S Silva
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
| | - Filipa Gonçalves
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
| | - João P Canejo
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
| | - Pedro L Almeida
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal. and Área Departamental de Física, Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, 1959-007 Lisbon, Portugal
| | - Maria Helena Godinho
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy.
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21
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Wan G, Jin C, Trase I, Zhao S, Chen Z. Helical Structures Mimicking Chiral Seedpod Opening and Tendril Coiling. Sensors (Basel) 2018; 18:E2973. [PMID: 30200611 PMCID: PMC6164363 DOI: 10.3390/s18092973] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 08/24/2018] [Accepted: 09/03/2018] [Indexed: 12/30/2022]
Abstract
Helical structures are ubiquitous in natural and engineered systems across multiple length scales. Examples include DNA molecules, plants' tendrils, sea snails' shells, and spiral nanoribbons. Although this symmetry-breaking shape has shown excellent performance in elastic springs or propulsion generation in a low-Reynolds-number environment, a general principle to produce a helical structure with programmable geometry regardless of length scales is still in demand. In recent years, inspired by the chiral opening of Bauhinia variegata's seedpod and the coiling of plant's tendril, researchers have made significant breakthroughs in synthesizing state-of-the-art 3D helical structures through creating intrinsic curvatures in 2D rod-like or ribbon-like precursors. The intrinsic curvature results from the differential response to a variety of external stimuli of functional materials, such as hydrogels, liquid crystal elastomers, and shape memory polymers. In this review, we give a brief overview of the shape transformation mechanisms of these two plant's structures and then review recent progress in the fabrication of biomimetic helical structures that are categorized by the stimuli-responsive materials involved. By providing this survey on important recent advances along with our perspectives, we hope to solicit new inspirations and insights on the development and fabrication of helical structures, as well as the future development of interdisciplinary research at the interface of physics, engineering, and biology.
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Affiliation(s)
- Guangchao Wan
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA.
| | - Congran Jin
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA.
| | - Ian Trase
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA.
| | - Shan Zhao
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA.
| | - Zi Chen
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA.
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22
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Abstract
It is a challenging task to realize the vision of hierarchically structured nanomaterials for large-scale applications. Herein, the biomaterial wood as a large-scale biotemplate for functionalization at multiple scales is discussed, to provide an increased property range to this renewable and CO2 -storing bioresource, which is available at low cost and in large quantities. The Progress Report reviews the emerging field of functional wood materials in view of the specific features of the structural template and novel nanotechnological approaches for the development of wood-polymer composites and wood-mineral hybrids for advanced property profiles and new functions.
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Affiliation(s)
- Lars A Berglund
- Department of Fiber and Polymer Technology, Wallenberg Wood Science Center, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
| | - Ingo Burgert
- ETH Zürich, Institute for Building Materials, Stefano-Franscini-Platz 3, 8093, Zurich, Switzerland
- EMPA-Swiss Federal Laboratories for Material Testing and Research, Applied Wood Research Laboratory, Dübendorf, 8600, Switzerland
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23
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Almeida APC, Canejo JP, Fernandes SN, Echeverria C, Almeida PL, Godinho MH. Cellulose-Based Biomimetics and Their Applications. Adv Mater 2018; 30:e1703655. [PMID: 29333680 DOI: 10.1002/adma.201703655] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/20/2017] [Indexed: 05/15/2023]
Abstract
Nature has been producing cellulose since long before man walked the surface of the earth. Millions of years of natural design and testing have resulted in cellulose-based structures that are an inspiration for the production of synthetic materials based on cellulose with properties that can mimic natural designs, functions, and properties. Here, five sections describe cellulose-based materials with characteristics that are inspired by gratings that exist on the petals of the plants, structurally colored materials, helical filaments produced by plants, water-responsive materials in plants, and environmental stimuli-responsive tissues found in insects and plants. The synthetic cellulose-based materials described herein are in the form of fibers and films. Fascinating multifunctional materials are prepared from cellulose-based liquid crystals and from composite cellulosic materials that combine functionality with structural performance. Future and recent applications are outlined.
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Affiliation(s)
- Ana P C Almeida
- i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516, Caparica, Portugal
| | - João P Canejo
- i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516, Caparica, Portugal
| | - Susete N Fernandes
- i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516, Caparica, Portugal
| | - Coro Echeverria
- i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516, Caparica, Portugal
| | - Pedro L Almeida
- i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516, Caparica, Portugal
- Área Departamental de Física, Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, 1959-007, Lisbon, Portugal
| | - Maria H Godinho
- i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516, Caparica, Portugal
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24
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Gallenmüller F, Langer M, Poppinga S, Kassemeyer HH, Speck T. Spore liberation in mosses revisited. AoB Plants 2018; 10:plx075. [PMID: 29372045 PMCID: PMC5777488 DOI: 10.1093/aobpla/plx075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/21/2017] [Indexed: 05/22/2023]
Abstract
The ability to perform hygroscopic movements has evolved in many plant lineages and relates to a multitude of different functions such as seed burial, flower protection or regulation of diaspore release. In most mosses, spore release is controlled by hygroscopic movements of the peristome teeth and also of the spore capsule. Our study presents, for the first time, temporally and spatially well-resolved kinematic analyses of these complex shape changes in response to humidity conditions and provides insights into the sophisticated functional morphology and anatomy of the peristome teeth. In Brachythecium populeum the outer teeth of the peristome perform particularly complex hygroscopic movements during hydration and desiccation. Hydration induces fast inward dipping followed by partial re-straightening of the teeth. In their final shape, wet teeth close the capsule. During desiccation, the teeth perform an outward flicking followed by a re-straightening which opens the capsule. We present a kinematic analysis of these shape changes and of the underlying functional anatomy of the teeth. These teeth are shown to be composed of two layers which show longitudinal gradients in their material composition, structure and geometry. We hypothesize that these gradients result in (i) differences in swelling/shrinking capacity and velocity between the two layers composing the teeth, and in (ii) a gradient of velocity of swelling and shrinking from the tip to the base of the teeth. We propose these processes explain the observed movements regulating capsule opening or closing. This hypothesis is corroborated by experiments with isolated layers of peristome teeth. During hydration and desiccation, changes to the shape and mass of the whole spore capsule accompany the opening and closing. Results are discussed in relation to their significance for humidity-based regulation of spore release.
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Affiliation(s)
- Friederike Gallenmüller
- Plant Biomechanics Group, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany
- Corresponding author’s e-mail address:
| | - Max Langer
- Plant Biomechanics Group, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany
| | - Simon Poppinga
- Plant Biomechanics Group, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany
- Freiburg Materials Research Center (FMF), Freiburg im Breisgau, Germany
| | - Hanns-Heinz Kassemeyer
- Department of Biology, State Institute of Viticulture and Enology, Freiburg im Breisgau, Germany
| | - Thomas Speck
- Plant Biomechanics Group, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany
- Freiburg Materials Research Center (FMF), Freiburg im Breisgau, Germany
- Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT), Freiburg im Breisgau, Germany
- Competence Network Biomimetic, Freiburg im Breisgau, Germany
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25
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Shin B, Ha J, Lee M, Park K, Park GH, Choi TH, Cho KJ, Kim HY. Hygrobot: A self-locomotive ratcheted actuator powered by environmental humidity. Sci Robot 2018; 3:3/14/eaar2629. [DOI: 10.1126/scirobotics.aar2629] [Citation(s) in RCA: 201] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 01/03/2018] [Indexed: 12/31/2022]
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26
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Lubecka EA, Liwo A. A general method for the derivation of the functional forms of the effective energy terms in coarse-grained energy functions of polymers. II. Backbone-local potentials of coarse-grained O1→4-bonded polyglucose chains. J Chem Phys 2017; 147:115101. [DOI: 10.1063/1.4994130] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Emilia A. Lubecka
- Institute of Informatics, University of Gdańsk, Wita Stwosza 57, 80-308 Gdańsk, Poland
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Adam Liwo
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
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27
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Abstract
Many plants show some form of helical growth, such as the circular searching movements of growing stems and other organs (circumnutation), tendril coiling, leaf and bud reversal (resupination), petal arrangement (contortion) and leaf blade twisting. Recent genetic findings have revealed that such helical growth may be associated with helical arrays of cortical microtubules and of overlying cellulose microfibrils. An alternative mechanism of coiling that is based on differential contraction within a bilayer has also recently been identified and underlies at least some of these growth patterns. Here, I provide an overview of the genes and cellular processes that underlie helical patterning. I also discuss the diversity of helical growth patterns in plants, highlighting their potential adaptive significance and comparing them with helical growth patterns in animals.
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Affiliation(s)
- David R Smyth
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
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28
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Affiliation(s)
| | - Worarin Meesorn
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Dafni Moatsou
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Christoph Weder
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
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29
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Borowska-Wykręt D, Rypień A, Dulski M, Grelowski M, Wrzalik R, Kwiatkowska D. Gradient of structural traits drives hygroscopic movements of scarious bracts surrounding Helichrysum bracteatum capitulum. Ann Bot 2017; 119:1365-1383. [PMID: 28334385 PMCID: PMC5604587 DOI: 10.1093/aob/mcx015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Accepted: 01/30/2017] [Indexed: 05/31/2023]
Abstract
Background and Aims The capitulum of Helichrysum bracteatum is surrounded by scarious involucral bracts that perform hygroscopic movements leading to bract bending toward or away from the capitulum, depending on cell wall water status. The present investigation aimed at explaining the mechanism of these movements. Methods Surface strain and bract shape changes accompanying the movements were quantified using the replica method. Dissection experiments were used to assess the contribution of different tissues in bract deformation. Cell wall structure and composition were examined with the aid of light and electron microscopy as well as confocal Raman spectroscopy. Key Results At the bract hinge (organ actuator) longitudinal strains at opposite surfaces differ profoundly. This results in changes of hinge curvature that drive passive displacement of distal bract portions. The distal portions in turn undergo nearly uniform strain on both surfaces and also minute shape changes. The hinge is built of sclerenchyma-like abaxial tissue, parenchyma and adaxial epidermis with thickened outer walls. Cell wall composition is rather uniform but tissue fraction occupied by cell walls, cell wall thickness, compactness and cellulose microfibril orientation change gradually from abaxial to adaxial hinge surface. Dissection experiments show that the presence of part of the hinge tissues is enough for movements. Conclusions Differential strain at the hinge is due to adaxial-abaxial gradient in structural traits of hinge tissues and cell walls. Thus, the bract hinge of H. bracteatum is a structure comprising gradually changing tissues, from highly resisting to highly active, rather than a bi-layered structure with distinct active and resistance parts, often ascribed for hygroscopically moving organs.
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Affiliation(s)
- Dorota Borowska-Wykręt
- Department of Biophysics and Morphogenesis of Plants, Faculty of Biology and Environment Protection, University of Silesia in Katowice, Jagiellońska 28, 40-032 Katowice, Poland
| | - Aleksandra Rypień
- Department of Biophysics and Morphogenesis of Plants, Faculty of Biology and Environment Protection, University of Silesia in Katowice, Jagiellońska 28, 40-032 Katowice, Poland
| | - Mateusz Dulski
- Institute of Material Science, University of Silesia in Katowice, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland
- Silesian Center for Education and Interdisciplinary Research, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland
| | - Michał Grelowski
- Department of Biophysics and Morphogenesis of Plants, Faculty of Biology and Environment Protection, University of Silesia in Katowice, Jagiellońska 28, 40-032 Katowice, Poland
- A. Chełkowski Institute of Physics, University of Silesia in Katowice, Uniwersytecka 4, 40-007 Katowice, Poland
| | - Roman Wrzalik
- Silesian Center for Education and Interdisciplinary Research, 75 Pułku Piechoty 1A, 41-500 Chorzów, Poland
- A. Chełkowski Institute of Physics, University of Silesia in Katowice, Uniwersytecka 4, 40-007 Katowice, Poland
| | - Dorota Kwiatkowska
- Department of Biophysics and Morphogenesis of Plants, Faculty of Biology and Environment Protection, University of Silesia in Katowice, Jagiellońska 28, 40-032 Katowice, Poland
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30
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Jeon SJ, Hayward RC. Reconfigurable Microscale Frameworks from Concatenated Helices with Controlled Chirality. Adv Mater 2017; 29:1606111. [PMID: 28221713 DOI: 10.1002/adma.201606111] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Indexed: 06/06/2023]
Abstract
The utility of helical structures in driving motion of microorganisms and plants has inspired efforts to develop synthetic stimuli-responsive helical architectures for self-motile and shape-morphing systems. While several approaches to responsive helices based on hydrogels and liquid crystalline polymers have been reported, they have so far been limited to macroscopic (cm scale) dimensions, and have not been applied to concatenated helices with more than two segments. Here, a robust method for microfabrication of helices inspired by Bauhinia seedpods, based on trilayer samples consisting of rigid plastic stripes sandwiching a swellable temperature-responsive hydrogel, is reported and the formation of responsive shape-controlled frameworks from concatenated multiple helices (multihelices) with controlled chirality is demonstrated. The block angle at each helical junction is controlled by the change in stripe direction, while the torsion angle defined by each segment of three helices is prescribed by the net twist of the middle segment, providing simple geometric design rules for the fabrication of complex 3D structures. This work opens new directions in programming 3D shapes by providing new insight into helical segments as building blocks, with potential applicability to the fabrication of scaffolds for cell culture, reconfigurable microfluidic channels, and microswimmers.
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Affiliation(s)
- Seog-Jin Jeon
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Ryan C Hayward
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA, 01003, USA
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31
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Abstract
Recent advances in limb regeneration are revealing the molecular events that integrate growth control, cell fate programming, and positional information to yield the exquisite replacement of the amputated limb. Parallel progress in several invertebrate and vertebrate models has provided a broader context for understanding the mechanisms and the evolution of regeneration. Together, these discoveries provide a foundation for describing the principles underlying regeneration of complex, multi-tissue structures. As such these findings should provide a wealth of ideas for engineers seeking to reconstitute regeneration from constituent parts or to elicit full regeneration from partial regeneration events.
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Affiliation(s)
- Elly M Tanaka
- DFG Research Center for Regenerative Therapies, Technische Universität Dresden Fetscherstrasse 105, 01307 Dresden, GERMANY.
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32
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Abstract
Helices are ubiquitous in nature, and helical shape transition is often observed in residually stressed bodies, such as composites, wherein materials with different mechanical properties are glued firmly together to form a whole body. Inspired by a variety of biological examples, the basic physical mechanism responsible for the emergence of twisting and bending in such thin composite structures has been extensively studied. Here, we propose a simplified analytical model wherein a slender membrane tube undergoes a helical transition driven by the contraction of an elastic ribbon bound to the membrane surface. We analytically predict the curvature and twist of an emergent helix as functions of differential strains and elastic moduli, which are confirmed by our numerical simulations. Our results may help understand shapes observed in different biological systems, such as spiral bacteria, and could be applied to novel designs of soft machines and robots.
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Affiliation(s)
- Hirofumi Wada
- Department of Physics, Ritsumeikan University, Kusatsu, 525-8577 Shiga, Japan.
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33
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Abstract
Shape-morphing systems can be found in many areas, including smart textiles, autonomous robotics, biomedical devices, drug delivery and tissue engineering. The natural analogues of such systems are exemplified by nastic plant motions, where a variety of organs such as tendrils, bracts, leaves and flowers respond to environmental stimuli (such as humidity, light or touch) by varying internal turgor, which leads to dynamic conformations governed by the tissue composition and microstructural anisotropy of cell walls. Inspired by these botanical systems, we printed composite hydrogel architectures that are encoded with localized, anisotropic swelling behaviour controlled by the alignment of cellulose fibrils along prescribed four-dimensional printing pathways. When combined with a minimal theoretical framework that allows us to solve the inverse problem of designing the alignment patterns for prescribed target shapes, we can programmably fabricate plant-inspired architectures that change shape on immersion in water, yielding complex three-dimensional morphologies.
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Affiliation(s)
- A Sydney Gladman
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - Elisabetta A Matsumoto
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - Ralph G Nuzzo
- School of Chemical Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
| | - L Mahadevan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, Massachusetts 02138, USA
- Departments of Physics and Organismic and Evolutionary Biology, and Kavli Institute for NanoBio Science and Technology, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - Jennifer A Lewis
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, Massachusetts 02138, USA
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34
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Chen P, Xu Y, He S, Sun X, Pan S, Deng J, Chen D, Peng H. Hierarchically arranged helical fibre actuators driven by solvents and vapours. Nat Nanotechnol 2015; 10:1077-1083. [PMID: 26367106 DOI: 10.1038/nnano.2015.198] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 07/31/2015] [Indexed: 06/05/2023]
Abstract
Mechanical responsiveness in many plants is produced by helical organizations of cellulose microfibrils. However, simple mimicry of these naturally occurring helical structures does not produce artificial materials with the desired tunable actuations. Here, we show that actuating fibres that respond to solvent and vapour stimuli can be created through the hierarchical and helical assembly of aligned carbon nanotubes. Primary fibres consisting of helical assemblies of multiwalled carbon nanotubes are twisted together to form the helical actuating fibres. The nanoscale gaps between the nanotubes and micrometre-scale gaps among the primary fibres contribute to the rapid response and large actuation stroke of the actuating fibres. The compact coils allow the actuating fibre to rotate reversibly. We show that these fibres, which are lightweight, flexible and strong, are suitable for a variety of applications such as energy-harvesting generators, deformable sensing springs and smart textiles.
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Affiliation(s)
- Peining Chen
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China
| | - Yifan Xu
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China
| | - Sisi He
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China
| | - Xuemei Sun
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China
| | - Shaowu Pan
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China
| | - Jue Deng
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China
| | - Daoyong Chen
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China
| | - Huisheng Peng
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, and Laboratory of Advanced Materials, Fudan University, Shanghai 200438, China
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35
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Li Y, Chen X, Fok A, Rodriguez-Cabello JC, Aparicio C. Biomimetic Mineralization of Recombinamer-Based Hydrogels toward Controlled Morphologies and High Mineral Density. ACS Appl Mater Interfaces 2015; 7:25784-25792. [PMID: 26516652 PMCID: PMC7476219 DOI: 10.1021/acsami.5b07628] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The use of insoluble organic matrices as a structural template for the bottom-up fabrication of organic-inorganic nanocomposites is a powerful way to build a variety of advanced materials with defined and controlled morphologies and superior mechanical properties. Calcium phosphate mineralization in polymeric hydrogels is receiving significant attention in terms of obtaining biomimetic hierarchical structures with unique mechanical properties and understanding the mechanisms of the biomineralization process. However, integration of organic matrices with hydroxyapatite nanocrystals, different in morphology and composition, has not been well-achieved yet at nanoscale. In this study, we synthesized thermoresponsive hydrogels, composed of elastin-like recombinamers (ELRs), to template mineralization of hydroxyapatite nanocrystals using a biomimetic polymer-induced liquid-precursor (PILP) mineralization process. Different from conventional mineralization where minerals were deposited on the surface of organic matrices, they were infiltrated into the frameworks of ELR matrices, preserving their microporous structure. After 14 days of mineralization, an average of 78 μm mineralization depth was achieved. Mineral density up to 1.9 g/cm(3) was found after 28 days of mineralization, which is comparable to natural bone and dentin. In the dry state, the elastic modulus and hardness of the mineralized hydrogels were 20.3 ± 1.7 and 0.93 ± 0.07 GPa, respectively. After hydration, they were reduced to 4.50 ± 0.55 and 0.10 ± 0.03 GPa, respectively. These values were lower but still on the same order of magnitude as those of natural hard tissues. The results indicated that inorganic-organic hybrid biomaterials with controlled morphologies can be achieved using organic templates of ELRs. Notably, the chemical and physical properties of ELRs can be tuned, which might help elucidate the mechanisms by which living organisms regulate the mineralization process.
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Affiliation(s)
- Yuping Li
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Xi Chen
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Alex Fok
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | | | - Conrado Aparicio
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, Minneapolis, Minnesota 55455, United States
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36
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Abstract
Pine cones fold their scales when it rains to prevent seeds from short-distance dispersal. Given that the scales of pine cones consist of nothing but dead cells, this folding motion is evidently related to structural changes. In this study, the structural characteristics of pine cones are studied on micro-/macro-scale using various imaging instruments. Raindrops fall along the outer scales to the three layers (bract scales, fibers and innermost lignified structure) of inner pine cones. However, not all the layers but only the bract scales get wet and then, most raindrops move to the inner scales. These systems reduce the amount of water used and minimize the time spent on structural changes. The result shows that the pine cones have structural advantages that could influence the efficient motion of pine cones. This study provides new insights to understand the motion of pine cones and would be used to design a novel water transport system.
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37
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Abstract
The seed capsule of Delosperma nakurense is a remarkable example of a natural hygromorph, which unfolds its protecting valves upon wetting to expose its seeds. The beautiful mechanism responsible for this motion is generated by a specialized organ based on an anisotropic cellular tissue filled with a highly swelling material. Inspired by this system, we study the mechanics of a diamond honeycomb internally pressurized by a fluid phase. Numerical homogenization by means of iterative finite-element (FE) simulations is adapted to the case of cellular materials filled with a variable pressure fluid phase. Like its biological counterpart, it is shown that the material architecture controls and guides the otherwise unspecific isotropic expansion of the fluid. Deformations up to twice the original dimensions can be achieved by simply setting the value of input pressure. In turn, these deformations cause a marked change of the honeycomb geometry and hence promote a stiffening of the material along the weak direction. To understand the mechanism further, we also developed a micromechanical model based on the Born model for crystal elasticity to find an explicit relation between honeycomb geometry, swelling eigenstrains and elastic properties. The micromechanical model is in good qualitative agreement with the FE simulations. Moreover, we also provide the force-stroke characteristics of a soft actuator based on the pressurized anisotropic honeycomb and show how the internal pressure has a nonlinear effect which can result in negative values of the in-plane Poisson's ratio. As nature shows in the case of the D. nakurense seed capsule, cellular materials can be used not only as low-weight structural materials, but also as simple but convenient actuating materials.
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Affiliation(s)
- Lorenzo Guiducci
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Peter Fratzl
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Yves J M Bréchet
- CEA-Atomic Energy and Alternative Energies Commission, Gif-sur-Yvette, Paris, France
| | - John W C Dunlop
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
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38
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Rafsanjani A, Brulé V, Western TL, Pasini D. Hydro-responsive curling of the resurrection plant Selaginella lepidophylla. Sci Rep 2015; 5:8064. [PMID: 25623361 PMCID: PMC4306918 DOI: 10.1038/srep08064] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/31/2014] [Indexed: 11/16/2022] Open
Abstract
The spirally arranged stems of the spikemoss Selaginella lepidophylla, an ancient resurrection plant, compactly curl into a nest-ball shape upon dehydration. Due to its spiral phyllotaxy, older outer stems on the plant interlace and envelope the younger inner stems forming the plant centre. Stem curling is a morphological mechanism that limits photoinhibitory and thermal damages the plant might experience in arid environments. Here, we investigate the distinct conformational changes of outer and inner stems of S. lepidophylla triggered by dehydration. Outer stems bend into circular rings in a relatively short period of desiccation, whereas inner stems curl slowly into spirals due to hydro-actuated strain gradient along their length. This arrangement eases both the tight packing of the plant during desiccation and its fast opening upon rehydration. The insights gained from this work shed light on the hydro-responsive movements in plants and might contribute to the development of deployable structures with remarkable shape transformations in response to environmental stimuli.
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Affiliation(s)
- Ahmad Rafsanjani
- Mechanical Engineering Department, McGill University, 817 Sherbrooke Street West, Montréal, QC, H3A OC3, Canada
| | - Véronique Brulé
- Biology Department, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, H3A 1B1, Canada
| | - Tamara L Western
- Biology Department, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, H3A 1B1, Canada
| | - Damiano Pasini
- Mechanical Engineering Department, McGill University, 817 Sherbrooke Street West, Montréal, QC, H3A OC3, Canada
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39
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Razghandi K, Bertinetti L, Guiducci L, Dunlop JWC, Fratzl P, Neinhuis C, Burgert I. Hydro-actuation of ice plant seed capsules powered by water uptake. Bioinspired, Biomimetic and Nanobiomaterials 2014. [DOI: 10.1680/bbn.14.00016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Unlike well-known plant hydro-actuation systems that respond to changes in relative humidity (RH) (e.g. wheat awns), ice plant seed capsules undergo a reversible origami-like unfolding and release their seeds only in response to exposure to liquid water. The engine for ice plant actuation was found to be the water uptake and swelling of a highly swellable cellulosic inner layer (CIL) inside the cell lumen of a hygroscopic tissue responsible for the unfolding movement. CIL was found to have an open structure with porous lamellae filling the gap between denser cellulosic mats. Thermogravimetric analysis of water–CIL interaction showed that the initial enthalpy-driven adsorption of water can only account for increasing the moisture content up to about 0·4 mg/mg, which is not sufficient to initiate the actuation. By applying a combined chemo-mechanical model, we could show that the entropic gain of the system through further water uptake (40–350 wt%) is sufficient to accomplish a full opening of the seed capsules through a sophisticated design at various hierarchical levels of the system. The principles behind this actuation mechanism may inspire the development of hydro-responsive devices that, although being highly hydrophilic, only respond to liquid water and not to changes in RH.
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Affiliation(s)
- Khashayar Razghandi
- Research Fellow, Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
- ETHZ, Institute for Building Materials (IfB), Zurich, Switzerland
| | - Luca Bertinetti
- Doctor, Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - Lorenzo Guiducci
- Doctor, Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - John W. C. Dunlop
- Doctor, Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - Peter Fratzl
- Professor, Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - Christoph Neinhuis
- Professor, Technical University of Dresden, Institute for Botany, Dresden, Germany
| | - Ingo Burgert
- Professor, ETHZ, Institute for Building Materials (IfB), Zurich, Switzerland
- Empa, Applied Wood Materials, Dübendorf, Switzerland
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40
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Elbaum R, Abraham Y. Insights into the microstructures of hygroscopic movement in plant seed dispersal. Plant Sci 2014; 223:124-33. [PMID: 24767122 DOI: 10.1016/j.plantsci.2014.03.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 02/12/2014] [Accepted: 03/16/2014] [Indexed: 05/08/2023]
Abstract
As non-motile organisms, plants develop means to spread their progenies. Hygroscopic movement is a very common mechanism employed in seed dispersal. This type of movement is created when the tissue desiccates and the cell walls dry and shrink. A contraction force develops, the direction and strength of which depends on the architecture of the tissue. This force may be utilized for a simple release of seeds, their catapultion, and for pushing seeds along the soil to a germination locus. We review the formation of a bend, a twist and a coil within various dispersal apparatuses as a reaction to the dehydration of the tissue. We compare the microscopic structures of hygroscopic devices supporting slow or fast movement, adaptations to dry or wet climates, and single use versus repeated movement. We discuss the development of the disconnecting tissues in relation to the development of a hygroscopic mechanism. As plant cultivation is dependent on seed dispersal control, we demonstrate that during the domestication of sesame and wheat, seed dispersal is avoided not due to a defective hygroscopic tissue, but rather a missing dehiscence tissue. Seed dispersal is a crucial stage in the life cycle of plants. Thus, hygroscopic movement plays a central part in plant ecology and agriculture.
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Affiliation(s)
- Rivka Elbaum
- RH Smith Institute for Plant Sciences and genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 7010001, Israel.
| | - Yael Abraham
- RH Smith Institute for Plant Sciences and genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 7010001, Israel
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41
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Abstract
We present the results of a combined experimental and theoretical investigation of the mechanics of self-burial of some plant seeds whose morphologies respond to environmental changes in humidity. The seeds of Erodium and Pelargonium have hygroscopically responsive awns that play a critical role in their self-burial into soil. The awn, coiled in a dry state, uncoils to stretch linearly under highly humid condition because of a tilted arrangement of cellulose microfibrils in one of the layers of the awn's bilayered structure. By measuring the mechanical characteristics of the awns of Pelargonium carnosum, we find that the extensional force of the awn can be aptly modeled by the theory of elasticity for a coiled spring. We further show that although the resistance to the seed-head penetrating relatively coarse soils without spinning is large enough to block the digging seed, the rotation of the seed greatly reduces the soil's resistance down to a level the awn can easily overcome. Our mechanical analysis reveals that the self-burial of the seed is a sophisticated outcome of the helically coiled configuration of the awn.
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Affiliation(s)
- Wonjong Jung
- *Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744, Korea; Department of Mechanical Engineering, Sogang University, Seoul 121-742, Korea
| | - Wonjung Kim
- *Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744, Korea; Department of Mechanical Engineering, Sogang University, Seoul 121-742, Korea
| | - Ho-Young Kim
- *Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744, Korea; Department of Mechanical Engineering, Sogang University, Seoul 121-742, Korea
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42
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Wang JS, Wang G, Feng XQ, Kitamura T, Kang YL, Yu SW, Qin QH. Hierarchical chirality transfer in the growth of Towel Gourd tendrils. Sci Rep 2013; 3:3102. [PMID: 24173107 DOI: 10.1038/srep03102] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 10/16/2013] [Indexed: 11/29/2022] Open
Abstract
Chirality plays a significant role in the physical properties and biological functions of many biological materials, e.g., climbing tendrils and twisted leaves, which exhibit chiral growth. However, the mechanisms underlying the chiral growth of biological materials remain unclear. In this paper, we investigate how the Towel Gourd tendrils achieve their chiral growth. Our experiments reveal that the tendrils have a hierarchy of chirality, which transfers from the lower levels to the higher. The change in the helical angle of cellulose fibrils at the subcellular level induces an intrinsic torsion of tendrils, leading to the formation of the helical morphology of tendril filaments. A chirality transfer model is presented to elucidate the chiral growth of tendrils. This present study may help understand various chiral phenomena observed in biological materials. It also suggests that chirality transfer can be utilized in the development of hierarchically chiral materials having unique properties.
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43
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Abraham Y, Elbaum R. Hygroscopic movements in Geraniaceae: the structural variations that are responsible for coiling or bending. New Phytol 2013; 199:584-594. [PMID: 23574364 DOI: 10.1111/nph.12254] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 03/04/2013] [Indexed: 05/08/2023]
Abstract
The family Geraniaceae is characterized by a beak-like fruit, consisting of five seeds appended by a tapering awn. The awns exhibit coiling or bending hygroscopic movement as part of the seed dispersal strategy. Here we explain the variation in the hygroscopic reaction based on structural principles. We examined five representative species from three genera: Erodium, Geranium, and Pelargonium. Using X-ray diffraction, and electron and polarized light microscopy, we measured the cellulose microfibril angles in relation to the cell and cellulose helix axes. The behavior of separated single cells during dehydration was also examined. A bi-layered structure characterizes all the representative genera studied, with a hygroscopically contracting inner layer, and a stiff outer layer. We found that the cellulose arrangement in the inner layer is responsible for the type of awn deformation (coiling or bending). In three of the five awns examined, we identified an additional coiling outer sublayer, which adds coiling deformation to the awn. We divide the movements into three types: bending, coiling, and coiled-bending. All movement types are found in the Geranium genus. These characteristics are of importance for understanding the evolution of seed dispersal mechanisms in the Geraniaceae family.
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Affiliation(s)
- Yael Abraham
- The Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Rivka Elbaum
- The Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
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Abstract
Seeds provide the vital genetic link and dispersal agent between successive generations of plants. Without seed dispersal as a means of reproduction, many plants would quickly die out. Because plants lack any sort of mobility and remain in the same spot for their entire lives, they rely on seed dispersal to transport their offspring throughout the environment. This can be accomplished either collectively or individually; in any case as seeds ultimately abdicate their movement, they are at the mercy of environmental factors. Thus, seed dispersal strategies are characterized by robustness, adaptability, intelligence (both behavioral and morphological), and mass and energy efficiency (including the ability to utilize environmental sources of energy available): all qualities that advanced engineering systems aim at in general, and in particular those that need to enable complex endeavors such as space exploration. Plants evolved and adapted their strategy according to their environment, and taken together, they enclose many desirable characteristics that a space mission needs to have. Understanding in detail how plants control the development of seeds, fabricate structural components for their dispersal, build molecular machineries to keep seeds dormant up to the right moment and monitor the environment to release them at the right time could provide several solutions impacting current space mission design practices. It can lead to miniaturization, higher integration and packing efficiency, energy efficiency and higher autonomy and robustness. Consequently, there would appear to be good reasons for considering biomimetic solutions from plant kingdom when designing space missions, especially to other celestial bodies, where solid and liquid surfaces, atmosphere, etc constitute and are obviously parallel with the terrestrial environment where plants evolved. In this paper, we review the current state of biomimetics on seed dispersal to improve space mission design.
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Affiliation(s)
- Camilla Pandolfi
- Advanced Concepts Team, European Space Agency, Noordwijk, The Netherlands.
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Abstract
Plants move in very different ways and for different reasons, but some active carnivorous plants perform extraordinary motion: Their snap-, catapult- and suction traps perform very fast and spectacular motions to catch their prey after receiving mechanical stimuli. Numerous investigations have led to deeper insights into the physiology and biomechanics of these trapping devices, but they are far from being fully understood. We review concisely how plant movements are classified and how they follow principles that bring together speed, actuation and architecture of the moving organ. In particular, we describe and discuss how carnivorous plants manage to execute fast motion. We address open questions and assess the prospects for future studies investigating potential universal mechanisms that could be the basis of key characteristic features in plant movement such as stimulus transduction, post-stimulatory mechanical answers, and organ formation.
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Affiliation(s)
- Simon Poppinga
- Plant Biomechanics Group, Botanic Garden, Faculty of Biology, University of Freiburg, Freiburg im Breisgau, Germany.
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Abraham Y, Elbaum R. Quantification of microfibril angle in secondary cell walls at subcellular resolution by means of polarized light microscopy. New Phytol 2013; 197:1012-1019. [PMID: 23240639 DOI: 10.1111/nph.12070] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 10/27/2012] [Indexed: 05/08/2023]
Abstract
The cell walls constitute the mechanical support of plants. Crystalline cellulose building the walls forms rigid microfibrils that set the stiffness of the cell and the direction in which it expands during growth. Therefore, the determination of the directions of the microfibrils is important in both mechanical and developmental assays. We adapted polarized light microscopy to estimate the cellulose microfibril orientations at subcellular resolution. The optical information supplements X-ray scattering data, Raman microspectroscopy, and electron microscopy. We analyzed samples from three plant tissues: cells from an Araucaria excels branch, in which we revealed lower cellulose density in regions where the cell wall curvature becomes bigger, namely, the cell wall corners; a wheat (Triticum turgidum) awn's hygroscopically active region, which revealed a gradient in the cellulose microfibril angles that spans across four cell rows; and a stork's bill's (Erodium gruinum) coiling awn, which revealed that the cellulose in the cell wall is organized in two orientations seamed together, rather than in a continuous helix. The unique spatial information is easily obtained from microscopic specimens and further illuminates new aspects in the mechanical tissues.
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Affiliation(s)
- Yael Abraham
- The Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Rivka Elbaum
- The Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
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Zickler GA, Ruffoni D, Dunlop JWC, Elbaum R, Weinkamer R, Fratzl P, Antretter T. Finite element modeling of the cyclic wetting mechanism in the active part of wheat awns. Biointerphases 2012; 7:42. [PMID: 22791359 DOI: 10.1007/s13758-012-0042-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 06/15/2012] [Indexed: 11/28/2022] Open
Abstract
Many plant tissues and organs are capable of moving due to changes in the humidity of the environment, such as the opening of the seed capsule of the ice plant and the opening of the pine cone. These are fascinating examples for the materials engineer, as these tissues are non-living and move solely through the differential swelling of anisotropic tissues and in principle may serve as examples for the bio-inspired design of artificial actuators. In this paper, we model the microstructure of the wild wheat awn (Triticum turgidum ssp. dicoccoides) by finite elements, especially focusing on the specific microscopic features of the active part of the awn. Based on earlier experimental findings, cell walls are modeled as multilayered cylindrical tubes with alternating cellulose fiber orientation in successive layers. It is shown that swelling upon hydration of this system leads to the formation of gaps between the layers, which could act as valves, thus enabling the entry of water into the cell wall. This supports the hypothesis that this plywood-like arrangement of cellulose fibrils enhances the effect of ambient humidity by accelerated water or vapor diffusion along the gaps. The finite element model shows that a certain distribution of axially and tangentially oriented fibers is necessary to generate sufficient tensile stresses within the cell wall to open nanometer-sized gaps between cell wall layers.
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Affiliation(s)
- Gerald A Zickler
- Institute for Mechanics, Montanuniversitaet Leoben, Leoben, Austria.
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Aharoni H, Abraham Y, Elbaum R, Sharon E, Kupferman R. Emergence of spontaneous twist and curvature in non-euclidean rods: application to Erodium plant cells. Phys Rev Lett 2012; 108:238106. [PMID: 23003997 DOI: 10.1103/physrevlett.108.238106] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 04/22/2012] [Indexed: 06/01/2023]
Abstract
We present a limiting model for thin non-euclidean elastic rods. Originating from the three-dimensional (3D) reference metric of the rod, which is determined by its internal material structure, we derive a 1D reduced rod theory. Specifically, we show how the spontaneous twist and curvature of a rod emerge from the reference metric derivatives. Thus, the model allows calculating the unconstrained equilibrium configuration of a thin rod directly from its internal structure. The model is applied to the study of cells from members of the Geraniaceae plant family and their configurational response to dehydration. We show how the geometrical arrangement of cellulose fibrils on the cell walls determines the helical shapes of isolated cells.
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Affiliation(s)
- Hillel Aharoni
- Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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