Nanoscale Mechanical Characterisation of Amyloid Fibrils Discovered in a Natural Adhesive

Mostaert, Anika S.; Higgins, Michael J.; Fukuma, Takeshi; Rindi, Fabio; Jarvis, Suzanne P.

doi:10.1007/s10867-006-9023-y

Cited by 114 publications

(124 citation statements)

References 21 publications

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“…These resemble a pattern seen when unfolding globular proteins [30] or amyloidal beta structures [27] and cloned nanofiber proteins from spiderwebs [31]. Such a pattern was also observed in secretions of microorganisms that stick to underwater surfaces [32,33]. A hysteresis in stretching/relaxation, providing good energy dissipation during stretching is also present.…”

Section: Resultssupporting

confidence: 52%

Nanomechanics of new materials — AFM and computer modelling studies of trichoptera silk

et al. 2011

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Abstract:Caddisfly (Trichopera) can glue diverse material underwater with a silk fiber. This makes it a particularly interesting subject for biomimetcs. Better understanding of silk composition and structure could lead to an adhesive capable to close bleeding wounds or to new biomaterials. However, while spiderweb or silkworm secretion is well researched, caddisfly silk is still poorly understood. Here we report a first nanomechanical analysis of H. Angustipennis caddisfly silk fiber. An Atomic Force Microscope (AFM) imaging shows dense 150 nm bumps on silk surface, which can be identified as one of features responsible for its outstanding adhesive properties. AFM force spectroscopy at the fiber surface showed, among others, characteristic saw like pattern. This pattern is attributed to sacrificial bond stretching and enhances energy dissipation in mechanical deformation. Similarities of some force curves observed on Tegenaria domestica spiderweb and caddisfly silk are also discussed. Steered Molecular Dynamics simulations revealed that the strength of short components of Fib-H HA species molecules, abundant in Trichoptera silk is critically dependent on calcium presence.

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Section: Resultssupporting

confidence: 52%

Nanomechanics of new materials — AFM and computer modelling studies of trichoptera silk

et al. 2011

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“…The structure of a 20 layer fibril is built following the model reported in Ref. 27 and considering the average configuration resulting from minimization and relaxation procedures 37 . Assuming that the interaction is homogenous along the length of the fibrils, all possible configurations of two amyloid fibrils interacting laterally are taken into account (Fig.…”

Section: Adhesion Energy Calculation From Atomistic Simulationsmentioning

confidence: 99%

“…There are examples of amyloids used as bionanomaterials in the form of nanowires 10,[17][18][19] , scaffolds and (bio)templates 10,[20][21][22][23][24][25] , liquid crystals 26 , adhesives 27 and films 14 . This wide range of applications is justified by the amyloid's remarkable mechanical and thermal stability and by their chemical properties that can be tuned via the introduction of additional elements, including enzymes, metal ions, fluorophores, biotin or cytochromes.…”

Section: Introductionmentioning

confidence: 99%

Self-folding and aggregation of amyloid nanofibrils

2011

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Amyloids are highly organized protein filaments, rich in beta-sheet secondary structures that self-assemble to form dense plaques in brain tissues affected by severe neurodegenerative disorders (e.g. Alzheimer's Disease). Identified as natural functional materials in bacteria, in addition to their remarkable mechanical properties, amyloids have also been proposed as a platform for novel biomaterials in nanotechnology applications including nanowires, liquid crystals, scaffolds and thin films. Despite recent progress in the understanding amyloid structure and behavior, the latent selfassembly mechanism and the underlying adhesion forces that drive the aggregation process remain poorly understood. On the basis of previous full atomistic simulations, here we report a simple coarse-grain model to analyze the competition between adhesive forces and elastic deformation of amyloid fibrils. We use simple model system to investigate self-assembly mechanisms of fibrils, focused on the formation of self-folded nanorackets and nanorings, and thereby address a critical issue in linking the biochemical (Angstrom) to micrometer scales relevant for larger-scale states of functional amyloid materials. We investigate the effect of varying the interfibril adhesion energy on the structure and stability of self-folded nanorackets and nanorings and demonstrate that such aggregated amyloid fibrils are stable in such states even when the fibril-fibril interaction is relatively weak, suggesting a strong propensity towards aggregation, given that the constituting amyloid fibril lengths exceed a critical fibril length-scale of several hundred nanometers. We further present a simple approach to directly determine the interfibril adhesion strength from geometric measures. In addition to providing insight into the physics of aggregation of amyloid fibrils our model enables the analysis of large-scale amyloid plaques and presents a new method for the estimation and engineering of the adhesive forces responsible of the self-assembly process of amyloid nanostructures, filling a 2 gap that previously existed between full atomistic simulations of primarily ultra-short fibrils and much larger micrometer-scale amyloid aggregates. Via direct simulation of large-scale amyloid plaques consisting of hundreds of fibrils we demonstrate that the fibril length has a profound impact on their structure and mechanical properties, where critical fibril length-scale derived from our analysis defines the structure of amyloid plaques. A multi-scale modeling approach as used here, bridging the scales from Angstroms to micrometers, opens a wide range of possible nanotechnology applications by presenting a holistic framework that balances mechanical properties of individual fibrils, hierarchical self-assembly, and the adhesive forces determining their stability to facilitate the design of de novo amyloid materials.

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“…According to earlier experimental and theoretical studies these mechanical properties are related to their molecular structure [10,12]. The exceptional mechanical properties of amyloids make them good candidates for a wide range of potential technological applications, and specifically as new bionanomaterials utilizing them as nanowires [13][14][15][16], gels [17][18][19][20][21], scaffolds and biotemplates [13,[22][23][24][25][26][27], liquid crystals [28], adhesives [29] and biofilm materials [30]. These applications often imply the functionalization of the amyloid fibrils with the introduction of additional elements, including enzymes, metal ions, fluorophores, biotin or cytochromes.…”

mentioning

confidence: 99%

Failure of Aβ(1-40) amyloid fibrils under tensile loading

Paparcone

Buehler

2011

Biomaterials

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Amyloid fibrils and plaques are detected in the brain tissue of patients affected by Alzheimer's disease, but have also been found as part of normal physiological processes such as bacterial adhesion. Due to their highly organized structures, amyloid proteins have also been used for the development of novel nanomaterials, for a variety of applications including biomaterials for tissue engineering, nanolectronics, or optical devices. Past research on amyloid fibrils resulted in advances in identifying their mechanical properties, revealing a remarkable stiffness. However, the failure mechanism under tensile loading has not been elucidated yet, despite its importance for the understanding of key mechanical properties of amyloid fibrils and plaques as well as the growth and aggregation of amyloids into long fibers and plaques. Here we report a molecular level analysis of failure of amyloids under uniaxial tensile loading. Our molecular modeling results demonstrate that amyloid fibrils are extremely stiff with a Young's modulus in the range of 18-30 GPa, in good agreement with previous experimental and computational findings. The most important contribution of our study is our finding that amyloid fibrils fail at relatively small strains of 2.5% to 4%, and at stress levels in the range of 1.02 to 0.64 GPa, in good agreement with experimental findings. Notably, we find that the strength properties of amyloid fibrils are extremely length dependent, and that longer amyloid fibrils show drastically smaller failure strains and failure stresses. As a result, longer fibrils in excess of hundreds of nanometers to micrometers have a greatly enhanced propensity towards spontaneous fragmentation and failure. We use a combination of simulation results and simple theoretical models to define critical fibril lengths where distinct failure mechanisms dominate.

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Nanoscale Mechanical Characterisation of Amyloid Fibrils Discovered in a Natural Adhesive

Cited by 114 publications

References 21 publications

Nanomechanics of new materials — AFM and computer modelling studies of trichoptera silk

Nanomechanics of new materials — AFM and computer modelling studies of trichoptera silk

Self-folding and aggregation of amyloid nanofibrils

Failure of Aβ(1-40) amyloid fibrils under tensile loading

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