Thermodynamic modeling of a phase transformation in protein filaments with mechanical function

Protective egg capsules from whelks (intertidal marine gastropods) were recently demonstrated to derive their impressive mechanical behavior—reminiscent of the pseudoelastic behavior in some alloy systems from a reversible phase transition of component protein building blocks from a compact α -helic...

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Main Authors: F D Fischer, M J Harrington, P Fratzl
Format: Article
Language:English
Published: IOP Publishing 2013-01-01
Series:New Journal of Physics
Online Access:https://doi.org/10.1088/1367-2630/15/6/065004
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author F D Fischer
M J Harrington
P Fratzl
author_facet F D Fischer
M J Harrington
P Fratzl
author_sort F D Fischer
collection DOAJ
description Protective egg capsules from whelks (intertidal marine gastropods) were recently demonstrated to derive their impressive mechanical behavior—reminiscent of the pseudoelastic behavior in some alloy systems from a reversible phase transition of component protein building blocks from a compact α -helical conformation to a more extended softer conformation, called β *. This behavior was previously modeled under equilibrium conditions, demonstrating that the transition from the α - to β *-phase could account for the pronounced yield plateau and reversibility; however, a theoretical understanding of the non-equilibrium behaviors of the egg capsule (e.g. strain rate dependence and hysteresis) requires a new approach. Here, we modify the previously proposed model in order to address the time-dependent behaviors of the whelk egg capsule biopolymer. Our results indicate that hysteresis during cyclic loading originates from a mismatch between the speed of the mechanical driving force and the rate at which the phase transition occurs. Furthermore, the characteristic curved shape of the stress–strain plot arises from a nonlinear relationship between the transformation rate and the amount of applied load. These results have important implications for our understanding of the mechanics of biological polymers and may have implications for the design of biomimetic pseudoelastic polymers.
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spelling doaj.art-92e09db034364940877bfd35554197b02023-08-08T11:10:36ZengIOP PublishingNew Journal of Physics1367-26302013-01-0115606500410.1088/1367-2630/15/6/065004Thermodynamic modeling of a phase transformation in protein filaments with mechanical functionF D Fischer0M J Harrington1P Fratzl2Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Research Campus Golm , D-14424 Potsdam, Germany; Montanuniversität Leoben, Institute of Mechanics , A-8700 Leoben, AustriaDepartment of Biomaterials, Max Planck Institute of Colloids and Interfaces, Research Campus Golm , D-14424 Potsdam, GermanyDepartment of Biomaterials, Max Planck Institute of Colloids and Interfaces, Research Campus Golm , D-14424 Potsdam, GermanyProtective egg capsules from whelks (intertidal marine gastropods) were recently demonstrated to derive their impressive mechanical behavior—reminiscent of the pseudoelastic behavior in some alloy systems from a reversible phase transition of component protein building blocks from a compact α -helical conformation to a more extended softer conformation, called β *. This behavior was previously modeled under equilibrium conditions, demonstrating that the transition from the α - to β *-phase could account for the pronounced yield plateau and reversibility; however, a theoretical understanding of the non-equilibrium behaviors of the egg capsule (e.g. strain rate dependence and hysteresis) requires a new approach. Here, we modify the previously proposed model in order to address the time-dependent behaviors of the whelk egg capsule biopolymer. Our results indicate that hysteresis during cyclic loading originates from a mismatch between the speed of the mechanical driving force and the rate at which the phase transition occurs. Furthermore, the characteristic curved shape of the stress–strain plot arises from a nonlinear relationship between the transformation rate and the amount of applied load. These results have important implications for our understanding of the mechanics of biological polymers and may have implications for the design of biomimetic pseudoelastic polymers.https://doi.org/10.1088/1367-2630/15/6/065004
spellingShingle F D Fischer
M J Harrington
P Fratzl
Thermodynamic modeling of a phase transformation in protein filaments with mechanical function
New Journal of Physics
title Thermodynamic modeling of a phase transformation in protein filaments with mechanical function
title_full Thermodynamic modeling of a phase transformation in protein filaments with mechanical function
title_fullStr Thermodynamic modeling of a phase transformation in protein filaments with mechanical function
title_full_unstemmed Thermodynamic modeling of a phase transformation in protein filaments with mechanical function
title_short Thermodynamic modeling of a phase transformation in protein filaments with mechanical function
title_sort thermodynamic modeling of a phase transformation in protein filaments with mechanical function
url https://doi.org/10.1088/1367-2630/15/6/065004
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AT mjharrington thermodynamicmodelingofaphasetransformationinproteinfilamentswithmechanicalfunction
AT pfratzl thermodynamicmodelingofaphasetransformationinproteinfilamentswithmechanicalfunction