In situ elastic modulus measurements of ultrathin protein-rich organic layers in biosilica: towards deeper understanding of superior resistance to fracture of biocomposites

Zlotnikov, Igor; Shilo, Doron; Dauphin, Yannicke; Blumtritt, H.; Werner, P.; Zolotoyabko, E.; Fratzl, Peter

doi:10.1039/c3ra40574e

Cited by 31 publications

(18 citation statements)

References 22 publications

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“…Although the precise mechanical properties of the compliant organic interlayers have yet to be fully characterized, we incorporate their potential contributing effect into our model by assuming that σ 33 can be discontinuous across adjacent silica cylinders. The assumption that the interlayers are compliant compared with the silica cylinders is supported through recent mechanical characterization of spicules from Monorhaphis chuni (31,32), which is closely related to E. aspergillum, contains a similar bulk chemical composition (25), and is similarly laminated.…”

Section: Significancementioning

confidence: 80%

New functional insights into the internal architecture of the laminated anchor spicules of Euplectella aspergillum

Monn

Weaver

Zhang

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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To adapt to a wide range of physically demanding environmental conditions, biological systems have evolved a diverse variety of robust skeletal architectures. One such example, Euplectella aspergillum, is a sediment-dwelling marine sponge that is anchored into the sea floor by a flexible holdfast apparatus consisting of thousands of anchor spicules (long, hair-like glassy fibers). Each spicule is covered with recurved barbs and has an internal architecture consisting of a solid core of silica surrounded by an assembly of coaxial silica cylinders, each of which is separated by a thin organic layer. The thickness of each silica cylinder progressively decreases from the spicule's core to its periphery, which we hypothesize is an adaptation for redistributing internal stresses, thus increasing the overall strength of each spicule. To evaluate this hypothesis, we created a spicule structural mechanics model, in which we fixed the radii of the silica cylinders such that the force transmitted from the surface barbs to the remainder of the skeletal system was maximized. Compared with measurements of these parameters in the native sponge spicules, our modeling results correlate remarkably well, highlighting the beneficial nature of this elastically heterogeneous lamellar design strategy. The structural principles obtained from this study thus provide potential design insights for the fabrication of high-strength beams for load-bearing applications through the modification of their internal architecture, rather than their external geometry. structure-property relationship | structural biomaterial | biocomposite | variational analysis B iological structural materials such as nacre, tooth, bone, and fish scales (1-9) often exhibit remarkable mechanical properties, which can be directly attributed to their unique structure and composition (10)(11)(12)(13)(14)(15). Through the detailed analysis of these complex skeletal materials, useful design lessons can be extracted that can be used to guide the synthesis of synthetic constructs with novel performance metrics (16)(17)(18)(19)(20). The complex and mechanically robust cage-like skeletal system of the hexactinellid sponge Euplectella aspergillum has proved to be a particularly useful model system for investigating structure-function relationships in hierarchically ordered biological composites (21-25). The sponge is anchored to the sea floor by thousands of anchor spicules (long, hair-like skeletal elements), each of which measures ca. 50 μm in diameter and up to 10 cm in length ( Fig. 1 A and B). The distal end of each anchor spicule is capped with a terminal crown-like structure and is covered with a series of recurved barbs that secure the sponge into the soft sediments of the sea floor (Fig. 1C). The proximal regions of these spicules are in turn bundled together and cemented to the main vertical struts of the skeletal lattice.These spicules contain an elastically heterogeneous, lamellar internal structure and are composed of amorphous hydrated silica. Surrounding a thin ...

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Section: Significancementioning

confidence: 80%

New functional insights into the internal architecture of the laminated anchor spicules of Euplectella aspergillum

Monn

Weaver

Zhang

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…19,20 Advances in biomineralisation research shows how many organisms are known to drastically enhance the toughness of brittle ceramics, like calcium carbonate by adding just a few weight percentage of organic macromolecules. 21 To this regard, inhomogeneous distributions of nm-sized organic inclusions have been shown by small-angle X-ray scattering in individual calcitic crystallites extracted from specific mollusk shells thus creating an organic-inorganic material with enhanced mechanical properties. 22 To accommodate an inorganic matrix such as FeCO 3, which is the iron counterpart of calcite, a hybrid nanofiller could be used.…”

Section: Introductionmentioning

confidence: 99%

Siderite micro-modification for enhanced corrosion protection

et al. 2017

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Production of oil and gas results in the creation of carbon dioxide (CO2) which when wet is extremely corrosive owing to the speciation of carbonic acid. Severe production losses and safety incidents occur when carbon steel (CS) is used as a pipeline material if corrosion is not properly managed. Currently corrosion inhibitor (CI) chemicals are used to ensure that the material degradation rates are properly controlled; this imposes operational constraints, costs of deployment and environmental issues. In specific conditions, a naturally growing corrosion product known as siderite or iron carbonate (FeCO3) precipitates onto the internal pipe wall providing protection from electrochemical degradation. Many parameters influence the thermodynamics of FeCO3 precipitation which is generally favoured at high values of temperatures, pressure and pH. In this paper, a new approach for corrosion management is presented; micro-modifying the corrosion product. This novel mitigation approach relies on enhancing the crystallisation of FeCO3 and improving its density, protectiveness and mechanical properties. The addition of a silicon-rich nanofiller is shown to augment the growth of FeCO3 at lower pH and temperature without affecting the bulk pH. The hybrid FeCO3 exhibits superior general and localised corrosion properties. The findings herein indicate that it is possible to locally alter the environment in the vicinity of the corroding steel in order to grow a dense and therefore protective FeCO3 film via the incorporation of hybrid organic-inorganic silsesquioxane moieties. The durability and mechanical integrity of the film is also significantly improved.

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“…Nanoindentation is an ideal method to characterize mechanical properties of materials at that scale. Since the late 1990s, its application range has been extended to study biological materials such as bone, marine shells, silica sponges, and wood [2][3][4][5]. Typically, the experiments are performed in the environmental conditions of the measurement chamber that do not represent the natural state of the biological specimens.…”

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confidence: 99%

Characterizing moisture-dependent mechanical properties of organic materials: humidity-controlled static and dynamic nanoindentation of wood cell walls

Bertinetti

Hangen²,

Eder

et al. 2014

Philosophical Magazine

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(2015) Characterizing moisture-dependent mechanical properties of organic materials: humidity-controlled static and dynamic nanoindentation of wood cell walls, Philosophical Magazine, 95:16-18, 1992-1998, DOI: 10.1080/14786435.2014 Nanoindentation is an ideal technique to study local mechanical properties of a wide range of materials on the sub-micron scale. It has been widely used to investigate biological materials in the dry state; however, their properties are strongly affected by their moisture content, which until now has not been consistently controlled. In the present study, we developed an experimental set-up for measuring local mechanical properties of materials by nanoindentation in a controlled environment of relative humidity (RH) and temperature. The significance of this new approach in studying biological materials was demonstrated for the secondary cell wall layer (S2) in Spruce wood (Picea abies). The hardness of the cell wall layer decreased from an average of approximately 0.6 GPa at 6% RH down to approximately 0.2 GPa at 79% RH, corresponding to a reduction by a factor of 3. Under the same conditions, the indentation modulus also decreased by about 40%. The newly designed experimental set-up has a strong potential for a variety of applications involving the temperature-and humidity-dependent properties of biological and artificial organic nanocomposites.

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In situ elastic modulus measurements of ultrathin protein-rich organic layers in biosilica: towards deeper understanding of superior resistance to fracture of biocomposites

Abstract: Electronic supplementary information (ESI) available: sample preparation, modulus mapping, TEM and HAADF-STEM measurements, and finite element analysis. See

Cited by 31 publications

References 22 publications

New functional insights into the internal architecture of the laminated anchor spicules of Euplectella aspergillum

New functional insights into the internal architecture of the laminated anchor spicules of Euplectella aspergillum

Siderite micro-modification for enhanced corrosion protection

Characterizing moisture-dependent mechanical properties of organic materials: humidity-controlled static and dynamic nanoindentation of wood cell walls

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