Nature provides a wide range of materials with different functions and which may serve as a source of bio-inspiration for the materials scientist. The article takes the point of view that a ...successful translation of these ideas into the technical world requires more than the observation of nature. A thorough analysis of structure-function relations in natural tissues must precede the engineering of new bio-inspired materials. There are, indeed, many opportunities for lessons from the biological world: on growth and functional adaptation, about hierarchical structuring, on damage repair and self-healing. Biomimetic materials research is becoming a rapidly growing and enormously promising field. Serendipitous discovery from the observation of nature will be gradually replaced by a systematic approach involving the study of natural tissues in materials laboratories, the application of engineering principles to the further development of bio-inspired ideas and the generation of specific databases.
The bulk of Earth's biological materials consist of few base substances-essentially proteins, polysaccharides, and minerals-that assemble into large varieties of structures. Multifunctionality arises ...naturally from this structural complexity: An example is the combination of rigidity and flexibility in protein-based teeth of the squid sucker ring. Other examples are time-delayed actuation in plant seed pods triggered by environmental signals, such as fire and water, and surface nanostructures that combine light manipulation with mechanical protection or water repellency. Bioinspired engineering transfers some of these structural principles into technically more relevant base materials to obtain new, often unexpected combinations of material properties. Less appreciated is the huge potential of using bioinspired structural complexity to avoid unnecessary chemical diversity, enabling easier recycling and, thus, a more sustainable materials economy.
Collagen: Structure and Mechanicsprovides a cohesive introduction to this biological macromolecule and its many applications in biomaterials and tissue engineering. Graduate students and postdoctoral ...researchers in the fields of materials, (bio-)engineering, physics, chemistry and biology will gain an understanding of the structure and mechanical behavior of type I collagen and collagen-based tissues in vertebrates, across all length scales from the molecular (nano) to the organ (macro) level. Written in a clear and didactic manner, this volume includes current knowledge on the hierarchical structure, mechanical properties, in addition to a review of deformation and strengthening mechanisms. Collagen: Structure and Mechanics is an excellent reference for new researchers entering this area and serves as a basis for lecturing in the interdisciplinary field of biological materials science.
Actuation systems in plants as prototypes for bioinspired devices Burgert, Ingo; Fratzl, Peter
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
04/2009, Letnik:
367, Številka:
1893
Journal Article
Recenzirano
Plants have evolved a multitude of mechanisms to actuate organ movement. The osmotic influx and efflux of water in living cells can cause a rapid movement of organs in a predetermined direction. Even ...dead tissue can be actuated by a swelling or drying of the plant cell walls. The deformation of the organ is controlled at different levels of tissue hierarchy by geometrical constraints at the micrometre level (e.g. cell shape and size) and cell wall polymer composition at the nanoscale (e.g. cellulose fibril orientation). This paper reviews different mechanisms of organ movement in plants and highlights recent research in the field. Particular attention is paid to systems that are activated without any metabolism. The design principles of such systems may be particularly useful for a biomimetic translation into active technical composites and moving devices.
Dormancy is an evolutionarily conserved protective mechanism widely observed in nature. A pathological example is found during cancer metastasis, where cancer cells disseminate from the primary ...tumor, home to secondary organs, and enter a growth-arrested state, which could last for decades. Recent studies have pointed toward the microenvironment being heavily involved in inducing, preserving, or ceasing this dormant state, with a strong focus on identifying specific molecular mechanisms and signaling pathways. Increasing evidence now suggests the existence of an interplay between intracellular as well as extracellular biochemical and mechanical cues in guiding such processes. Despite the inherent complexities associated with dormancy, proliferation, and growth of cancer cells and tumor tissues, viewing these phenomena from a physical perspective allows for a more global description, independent from many details of the systems. Building on the analogies between tissues and fluids and thermodynamic phase separation concepts, we classify a number of proposed mechanisms in terms of a thermodynamic metastability of the tumor with respect to growth. This can be governed by interaction with the microenvironment in the form of adherence (wetting) to a substrate or by mechanical confinement of the surrounding extracellular matrix. By drawing parallels with clinical and experimental data, we advance the notion that the local energy minima, or metastable states, emerging in the tissue droplet growth kinetics can be associated with a dormant state. Despite its simplicity, the provided framework captures several aspects associated with cancer dormancy and tumor growth.
Protein‐metal interactions—traditionally regarded for roles in metabolic processes—are now known to enhance the performance of certain biogenic materials, influencing properties such as hardness, ...toughness, adhesion, and self‐healing. Design principles elucidated through thorough study of such materials are yielding vital insights for the design of biomimetic metallopolymers with industrial and biomedical applications. Recent advances in the understanding of the biological structure–function relationships are highlighted here with a specific focus on materials such as arthropod biting parts, mussel byssal threads, and sandcastle worm cement.
Protein–metal interactions were traditionally regarded for their role in metabolic processes. Nowadays, they are also known to enhance the performance of certain biogenic materials, influencing properties such as hardness, toughness, adhesion, and self‐healing. In this Review, recent advances in the understanding of the biological structure–function relationships are highlighted.
The Role of Wheat Awns in the Seed Dispersal Unit Elbaum, Rivka; Zaltzman, Liron; Burgert, Ingo ...
Science (American Association for the Advancement of Science),
05/2007, Letnik:
316, Številka:
5826
Journal Article
Recenzirano
The dispersal unit of wild wheat bears two pronounced awns that balance the unit as it falls. We discovered that the awns are also able to propel the seeds on and into the ground. The arrangement of ...cellulose fibrils causes bending of the awns with changes in humidity. Silicified hairs that cover the awns allow propulsion of the unit only in the direction of the seeds. This suggests that the dead tissue is analogous to a motor. Fueled by the daily humidity cycle, the awns induce the motility required for seed dispersal.
Structural patterns found in living organisms have long been inspiring biomimetic materials design. Here, it is suggested that a rich palette of patterns occurring in inanimate Nature, and especially ...in the Earth's lithosphere, could be not less inspirational for design of novel architectured materials. This materials design paradigm is referred to as lithomimetics and it is demonstrated that some of the patterns found in the lithosphere can be emulated by established processes of severe plastic deformation. This opens up interesting avenues for materials design in which potentially promising structural patterns are borrowed from the lithosphere's repository. The key aim here is to promulgate the “lithomimetics” paradigm as a promising approach to developing novel architectured materials.
A novel lithomimetic approach is proposed, which entails mimicking structures and processes occurring in the Earth's lithosphere to produce man‐made advanced materials. Severe plastic deformation is considered as a viable vehicle for that.
Osteocytes and their cell processes reside in a large, interconnected network of voids pervading the mineralized bone matrix of most vertebrates. This osteocyte lacuno-canalicular network (OLCN) is ...believed to play important roles in mechanosensing, mineral homeostasis, and for the mechanical properties of bone. While the extracellular matrix structure of bone is extensively studied on ultrastructural and macroscopic scales, there is a lack of quantitative knowledge on how the cellular network is organized. Using a recently introduced imaging and quantification approach, we analyze the OLCN in different bone types from mouse and sheep that exhibit different degrees of structural organization not only of the cell network but also of the fibrous matrix deposited by the cells. We define a number of robust, quantitative measures that are derived from the theory of complex networks. These measures enable us to gain insights into how efficient the network is organized with regard to intercellular transport and communication. Our analysis shows that the cell network in regularly organized, slow-growing bone tissue from sheep is less connected, but more efficiently organized compared to irregular and fast-growing bone tissue from mice. On the level of statistical topological properties (edges per node, edge length and degree distribution), both network types are indistinguishable, highlighting that despite pronounced differences at the tissue level, the topological architecture of the osteocyte canalicular network at the subcellular level may be independent of species and bone type. Our results suggest a universal mechanism underlying the self-organization of individual cells into a large, interconnected network during bone formation and mineralization.
The extensible byssal threads of marine mussels are shielded from abrasion in wave-swept habitats by an outer cuticle that is largely proteinaceous and approximately fivefold harder than the thread ...core. Threads from several species exhibit granular cuticles containing a protein that is rich in the catecholic amino acid 3,4-dihydroxyphenylalanine (dopa) as well as inorganic ions, notably Fe³⁺. Granular cuticles exhibit a remarkable combination of high hardness and high extensibility. We explored byssus cuticle chemistry by means of in situ resonance Raman spectroscopy and demonstrated that the cuticle is a polymeric scaffold stabilized by catecholato-iron chelate complexes having an unusual clustered distribution. Consistent with byssal cuticle chemistry and mechanics, we present a model in which dense cross-linking in the granules provides hardness, whereas the less cross-linked matrix provides extensibility.
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