Structural and mechanical aspects of the skin of Bufo marinus (Anura, Amphibia)

Schwinger, Gerhard; Zanger, Klaus; Greven, Hartmut

doi:10.1054/tice.2001.0208

Cited by 33 publications

(27 citation statements)

References 12 publications

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“…On the other hand, the enhanced understanding of keratins has fueled the research area of biological keratinous materials with the aim to create bioinspired materials. Some keratinized materials with interesting properties, such as skin [137], quills [138,139], fingernails [140], horns [141,142], whelk egg capsules [116], and bird feathers [143,144], have been studied, with the hopes to obtain mechanisms and principles to design new functional materials, such as light-weight composites, and energy-absorbent materials [145]. This is a new and fascinating area, awaiting more and in-depth explorations.…”

Section: Keratin Research Historymentioning

confidence: 99%

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Wang

Yang

McKittrick

et al. 2016

Progress in Materials Science

656

474

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a b s t r a c tA ubiquitous biological material, keratin represents a group of insoluble, usually high-sulfur content and filament-forming proteins, constituting the bulk of epidermal appendages such as hair, nails, claws, turtle scutes, horns, whale baleen, beaks, and feathers. These keratinous materials are formed by cells filled with keratin and are considered 'dead tissues'. Nevertheless, they are among the toughest biological materials, serving as a wide variety of interesting functions, e.g. scales to armor body, horns to combat aggressors, hagfish slime as defense against predators, nails and claws to increase prehension, hair and fur to protect against the environment. The vivid inspiring examples can offer useful solutions to design new structural and functional materials.Keratins can be classified as a-and b-types. Both show a characteristic filament-matrix structure: 7 nm diameter intermediate filaments for a-keratin, and 3 nm diameter filaments for b-keratin.Both are embedded in an amorphous keratin matrix. The molecular unit of intermediate filaments is a coiled-coil heterodimer and that of b-keratin filament is a pleated sheet. The mechanical response of a-keratin has been extensively studied and shows linear Hookean, yield and post-yield regions, and in some cases, a high reversible elastic deformation. Thus, they can be also be considered 'biopolymers'. On the other hand, b-keratin has not been investigated as comprehensively. Keratinous materials are strain-rate sensitive, and the effect of hydration is significant.Keratinous materials exhibit a complex hierarchical structure: polypeptide chains and filament-matrix structures at the nanoscale, Progress in Materials Science 76 (2016) 229-318 Contents lists available at ScienceDirect Progress in Materials Sciencej o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / p m a t s c i organization of keratinized cells into lamellar, tubular-intertubular, fiber or layered structures at the microscale, and solid, compact sheaths over porous core, sandwich or threads at the macroscale. These produce a wide range of mechanical properties: the Young's modulus ranges from 10 MPa in stratum corneum to about 2.5 GPa in feathers, and the tensile strength varies from 2 MPa in stratum corneum to 530 MPa in dry hagfish slime threads. Therefore, they are able to serve various functions including diffusion barrier, buffering external attack, energy-absorption, impact-resistance, piercing opponents, withstanding repeated stress and aerodynamic forces, and resisting buckling and penetration.A fascinating part of the new frontier of materials study is the development of bioinspired materials and designs. A comprehensive understanding of the biochemistry, structure and mechanical properties of keratins and keratinous materials is of great importance for keratin-based bioinspired materials and designs. Current bioinspired efforts including the manufacturing of quill-inspired aluminum composites, animal horn-inspired SiC composites, and feather-i...

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Section: Keratin Research Historymentioning

confidence: 99%

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Wang

Yang

McKittrick

et al. 2016

Progress in Materials Science

656

474

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“…We believe that the quantitative differences observed among regions within our data provide valid comparisons. In addition, because the majority of studies examining the mechanical properties of vertebrate integument have used only uniaxial tensile tests (Jayne, 1988;Bauer et al, 1989Bauer et al, , 1992Bauer et al, , 1993Brainerd, 1994;Greven et al, 1995;Zanger et al, 1995;Swartz et al, 1996;Schwinger et al, 2001), our use of this method allows for comparisons across taxa.…”

Section: Mechanics Of Snake Skinmentioning

confidence: 99%

Mechanical properties of the integument of the common gartersnake,Thamnophis sirtalis(Serpentes: Colubridae)

Rivera

Savitzky

Hinkley

2005

Journal of Experimental Biology

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SUMMARY The evolution of the ophidian feeding mechanism has involved substantial morphological restructuring associated with the ability to ingest relatively large prey. Previous studies examining the morphological consequences of macrophagy have concentrated on modifications of the skull and cephalic musculature. Although it is evident that macrophagy requires highly compliant skin, the mechanical properties of the ophidian integument have received limited attention, particularly in the context of feeding. We examined mechanical properties of skin along the body axis in Thamnophis sirtalis (Colubridae). Data were collected from tensile tests and were analyzed using a multivariate analysis of variance (MANOVA) and post-hoc multiple comparison tests. Significant differences in mechanical properties were detected among regions of the body. In general,prepyloric skin is more compliant than postpyloric skin, consistent with the demands of macrophagy.

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“…Oxytalan fibers in the superficial dermis extend from the dermoepidermal junction and are continuous to elaunin fibers aligned perpendicularly in the deeper papillary dermis, while the reticular dermis contains horizontally arranged thick elastic fibers (Kobayasi, 1968(Kobayasi, , 1977Cotta-Pereira et al, 1976, 1977Dahlbä ck et al, 1990). This spatial arrangement appears to be important architecturally and functionally and is conserved even in lower vertebrates (Ferri, 1980;Schwinger et al, 2001). In avian skin, an elastic fiber system is evolutionarily specialized to acquire regulated feather movement through a muscle-elastic fiber linkage (Lucas and Stettenheim, 1972;Starcher et al, 2005).…”

mentioning

confidence: 99%

Late Deposition of Elastin to Vertical Microfibrillar Fibers in the Presumptive Dermis of the Chick Embryonic Tarsometatarsus

Yamazaki

Sejima

Yuguchi

et al. 2007

The Anatomical Record

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Fibrillin microfibrils are integral components of elastic fibers and serve as a scaffold for elastin deposition. However, microfibrillar fibers (MFs) are not necessarily committed to develop into so-called elastic fibers. In dermis, elastin-free oxytalan MFs originating from the dermoepidermal junction are continuous to elaunin-type MFs (with a small amount of elastin) in the deeper papillary dermis, whereas the reticular dermis contains elastic fibers, or MFs embedded largely in elastin. In this study, we have investigated temporospatial patterns of elastin deposition on the MFs in tarsometatarsal presumptive dermis. While the earliest expression of elastin was demonstrated immunohistochemically as early as embryonic day 4 (ED4) in the wall of cardiac outflow and pharyngeal arch arteries, its deposition in the tarsometatarsus was first detected at ED6 in the deeper mesenchyme and at ED13 in the subectodermal mesenchyme. In the latter tissue, MFs had been organized perpendicularly to the covering ectoderm by ED4, well before an overt accumulation of collagenous matrix. Elastin deposition was observed initially in a punctate manner at ED13 and afterward became continuous along MFs. However, a characteristic spaced array of subectodermal vertical MFs was disorganized by ED17. These findings suggest that elastin deposition in the subectodermal MFs is not deployed by continuous, orderly propagation from elastic fibers in the deeper mesenchyme but occurs de novo in multiple foci along vertical MFs. Moreover, the present chronology of elastin deposition indicates that subectodermal, elastin-free MFs function as a transient, but primary fibrous structure in the presumptive dermis before the accumulation of collagenous matrix.

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Structural and mechanical aspects of the skin of Bufo marinus (Anura, Amphibia)

Cited by 33 publications

References 12 publications

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Mechanical properties of the integument of the common gartersnake,Thamnophis sirtalis(Serpentes: Colubridae)

Late Deposition of Elastin to Vertical Microfibrillar Fibers in the Presumptive Dermis of the Chick Embryonic Tarsometatarsus

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