Mechanisms of Load-Deformation Behavior of Molecular Collagen in Hydroxyapatite-Tropocollagen Molecular System: Steered Molecular Dynamics Study

Bhowmik, Rahul; Katti, Kalpana S.; Katti, Dinesh R.

doi:10.1061/(asce)0733-9399(2009)135:5(413)

Cited by 56 publications

(37 citation statements)

References 49 publications

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“…Existing collagen microfibril and fibril models represent the supramolecular arrangement in collagenous tissues in a simplified way, using a two-dimensional lattice of mesoscopic beads [43,44] or extremely short collagen peptides [30][31][32][33][34][35][36][37][38][39]. These models do not account for the biochemical details and are much smaller than the typical length-scales of collagen molecules found in collagen microfibrils and fibrils.…”

Section: Methodsmentioning

confidence: 99%

“…Most earlier studies, however, were based on ultrashort collagen-like peptides obtained from x-ray crystallography [26][27][28][29]. The early molecular simulation studies used these short collagen molecules [30][31][32][33][34][35][36][37][38][39] that were typically limited to less than 10 nm length or more than a factor of 30 smaller than actual molecules found in collagen tissues. The resulting elastic modulus of these short collagen peptides was found to be on the order of 4.8±2 GPa, and much greater than the typical Young's moduli measured for macro-scale collagen tissues but in agreement with single molecule studies [16,17,[40][41][42] (see Table 1 for an overview).…”

Section: Introductionmentioning

confidence: 99%

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Hierarchical Structure and Nanomechanics of Collagen Microfibrils from the Atomistic Scale Up

Gautieri

Vesentini²,

Redaelli³

et al. 2011

Nano Lett.

610

488

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Abstract:Collagen constitutes one third of the human proteome, providing mechanical stability, elasticity and strength to connective tissues. Collagen is also the dominating material in the extracellular matrix (ECM) and is thus crucial for cell differentiation, growth and pathology. However, fundamental questions remain with respect to the origin of the unique mechanical properties of collagenous tissues, and in particular its stiffness, extensibility and nonlinear mechanical response. By using x-ray diffraction data of a collagen fibril reported by Orgel et al.(Proceedings of the National Academy of Sciences USA, 2006) in combination with protein structure identification methods, here we present an experimentally validated model of the nanomechanics of a collagen microfibril that incorporates the full biochemical details of the amino acid sequence of the constituting molecules. We report the analysis of its mechanical properties under different levels of stress and solvent conditions, using a full-atomistic force field including explicit water solvent. Mechanical testing of hydrated collagen microfibrils yields a Young's modulus of ≈300 MPa at small and ≈1.2 GPa at larger deformation in excess of 10% strain, in excellent agreement with experimental data. Dehydrated, dry collagen microfibrils show a significantly increased Young's modulus of ≈1.8 to 2.25 GPa (or ≈6.75 times the modulus in the wet state) owing to a much tighter molecular packing, in good agreement with experimental measurements (where an increase of the modulus by ≈9 times was found). Our model demonstrates that the unique mechanical properties of collagen microfibrils can be explained based on their hierarchical structure, where deformation is mediated through mechanisms that operate at different hierarchical levels. Key mechanisms involve straightening of initially disordered and helically twisted molecules at small strains, followed by axial stretching of molecules, and eventual molecular uncoiling at extreme deformation. These mechanisms explain the striking difference of the modulus of collagen fibrils compared with single molecules, which is found in the range of 4.8±2 GPa or ≈10-20 times greater. These findings corroborate the notion that collagen tissue properties are highly scale dependent and nonlinear elastic, an issue that must be considered in the development of models that describe the interaction of cells with collagen in the extracellular matrix. A key impact the atomistic model of collagen microfibril mechanics reported here is that it enables the bottom-up elucidation of structure-property relationships in the broader class of collagen materials such as tendon or bone, including studies in the context of genetic disease where the incorporation of biochemical, genetic details in material models of connective tissue is essential.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hierarchical Structure and Nanomechanics of Collagen Microfibrils from the Atomistic Scale Up

Gautieri

Vesentini²,

Redaelli³

et al. 2011

Nano Lett.

610

488

View full text Add to dashboard Cite

show abstract

“…They predicted effective properties of chitin-protein fibers with a mean-field homogenization method. Molecular mechanics-based studies on the interfacial interactions in a multiphase composite system have also been performed using SMD to study the interfaces in collagen based materials by peeling off collagen filaments from the HAP substrates [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Influence of interfacial interactions on deformation mechanism and interface viscosity in α-chitin–calcite interfaces

Verma

Alucozai

et al. 2015

Acta Biomaterialia

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The interfaces between organic and inorganic phases in natural materials have a significant effect on their mechanical properties. This work presents a quantification of the interface stress as a function of interface chemical changes (water, organic molecules) in chitin-calcite (CHI-CAL) interfaces using classical non-equilibrium molecular dynamics (NEMD) simulations and steered molecular dynamics (SMD) simulations. NEMD is used to investigate interface stress as a function of applied strain based on the virial stress formulation. SMD is used to understand interface separation mechanism and to calculate interfacial shear stress based on a viscoplastic interfacial sliding model. Analyses indicate that interfacial shear stress combined with shear viscosity can result in variations to the mechanical properties of the examined interfacial material systems. It is further verified with Kelvin-Voigt and Maxwell viscoelastic analytical models representing viscous interfaces and outer matrix. Further analyses show that overall mechanical deformation depends on maximization of interface shear strength in such materials. This work establishes lower and upper bounds of interface strength in the interfaces examined.

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“…Computational models, using a finite-element method (FEM), were used in references Ji & Gao [13], Siegmund et al [14] and Yuan et al [15]. Molecular dynamics (MD) simulations were also used to study fibrillar collagen [2,16] and collagen -crystal interactions [17][18][19][20]. At sub-microscale, a single lamella was modelled computationally as a random network of preferentially oriented mineralized collagen fibrils [21] and analytically as a matrix-inclusion composite [9,10,12].…”

Section: Introductionmentioning

confidence: 99%

Multi-scale modelling of elastic moduli of trabecular bone

Hamed

Jasiuk

Yoo³

et al. 2012

J. R. Soc. Interface.

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We model trabecular bone as a nanocomposite material with hierarchical structure and predict its elastic properties at different structural scales. The analysis involves a bottom-up multi-scale approach, starting with nanoscale (mineralized collagen fibril) and moving up the scales to sub-microscale (single lamella), microscale (single trabecula) and mesoscale (trabecular bone) levels. Continuum micromechanics methods, composite materials laminate theory and finite-element methods are used in the analysis. Good agreement is found between theoretical and experimental results.

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Mechanisms of Load-Deformation Behavior of Molecular Collagen in Hydroxyapatite-Tropocollagen Molecular System: Steered Molecular Dynamics Study

Cited by 56 publications

References 49 publications

Hierarchical Structure and Nanomechanics of Collagen Microfibrils from the Atomistic Scale Up

Hierarchical Structure and Nanomechanics of Collagen Microfibrils from the Atomistic Scale Up

Influence of interfacial interactions on deformation mechanism and interface viscosity in α-chitin–calcite interfaces

Multi-scale modelling of elastic moduli of trabecular bone

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