Not only tendons: The other architecture of collagen fibrils

Raspanti, Mario; Reguzzoni, Marcella; Protasoni, Marina; Basso, Petra Rita

doi:10.1016/j.ijbiomac.2017.10.037

Cited by 23 publications

(36 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The distribution of collagen types within individual fibrils has been qualitatively assessed from immunoassay double-labeling. Both type I and type III are seen on fibril surfaces [36][37][38] indicative of homogeneity (the evidence is, however, mixed 34 ). Under the assumption that mixtures of collagen types are spatially homogeneous within a fibril, the elastic parameters of the mixture should be interpolations between those of the pure collagen types 29 .…”

Section: Influence Of Collagen Typesmentioning

confidence: 99%

“…vivo is correlated to the anatomical location of the fibril, as well as the type of tropocollagen found within the fibril 10,11,18,34,58 . Two well-studied fibril types in vivo are corneal fibrils, which have large surface twists 0.31 rad 16 , and tendon fibrils, which have fairly small surface twists 0.1 rad 59 .…”

Section: Comparison With In Vivo Fibril Ultrastructurementioning

confidence: 99%

See 1 more Smart Citation

Polymorphism of stable collagen fibrils

2018

View full text Add to dashboard Cite

Collagen fibrils are versatile self-assembled structures that provide mechanical integrity within mammalian tissues. The radius of collagen fibrils vary widely depending on experimental conditions in vitro or anatomical location in vivo. Here we explore the variety of thermodynamically stable fibril configurations that are available. We use a liquid crystal model of radial collagen fibril structure with a double-twist director field. Using a numerical relaxation method we show that two dimensionless parameters, the ratio of saddle-splay to twist elastic constants k24/K22 and the ratio of surface tension to chiral strength [small gamma, Greek, tilde] ≡ γ/(K22q), largely specify both the scaled fibril radius and the associated surface twist of equilibrium fibrils. We find that collagen fibrils are the stable phase with respect to the cholesteric phase only when the reduced surface tension is small, [small gamma, Greek, tilde] ⪅ 0.2. Within this stable regime, collagen fibrils can access a wide range of radii and associated surface twists. Remarkably, we find a maximal equilibrium surface twist of 0.33 rad (19°). Our results are compatible with corneal collagen fibrils, and we show how the large surface twist can explain the narrow distribution of corneal fibril radii. Conversely, we show how small surface twist is required for the thermodynamic stability of tendon fibrils in the face of considerable polydispersity of radius.

show abstract

Section: Influence Of Collagen Typesmentioning

confidence: 99%

Section: Comparison With In Vivo Fibril Ultrastructurementioning

confidence: 99%

Polymorphism of stable collagen fibrils

2018

View full text Add to dashboard Cite

show abstract

“…The chiral nature of collagen fibrils is evident in the tilted alignment of individual molecules with respect to the fibril axis [9][10][11][12][13]. This "twist" angle ψ can be as large as 17 • at the surface of corneal fibrils, and is approximately 5 • in tendon fibrils [2,14]. Theoretical work treating the fibril structure as a chiral liquid crystal [11,13,15] has shown that twisted fibrils can be thermodynamically stable, and predicts that twist continuously varies within the fibril as a "double-twist" field ψ(r).…”

mentioning

confidence: 99%

“…The "gap" and "overlap" regions of the Hodge-Petruska model suggest a D-band modulation amplitude that is 10% of the total density. However, a simple geometrical interpretation of the Hodge-Petruska model also locally implies a D-band period d ∝ cos ψ(r) within an individual fibril [2], whereas only a single D-band period is observed in experiment. One previous model of both D-band and double-twist therefore assumes a radially constant twist [19], though this is energetically unfavourable for the double-twist field [13].…”

mentioning

confidence: 99%

“…One previous model of both D-band and double-twist therefore assumes a radially constant twist [19], though this is energetically unfavourable for the double-twist field [13]. A second model has an approximately constant twist gradient [9], which is energetically preferable for the double-twist but implies local stretch-ing or compression of the D-band [2]. These two models of the radial twist ψ(r) represent the opposite limits of a stiff or soft D-band, respectively.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Phase-field collagen fibrils: Coupling chirality and density modulations

Cameron

Kreplak

Rutenberg

2020

Phys. Rev. Research

View full text Add to dashboard Cite

To describe the interaction between longitudinal density modulations along collagen fibrils (the D-band) with the radial twist-field of molecular orientation (double-twist), we couple phase-fieldcrystal (PFC) with liquid-crystalline free-energies to obtain a hybrid model of equilibrium collagen fibril structure. We numerically compute the resulting axial and radial structure. We find two distinct fibrillar phases, 'L' and 'C', with a coexistence line that ends in an Ising-like critical point. We propose that coexistence between these phases can explain the bimodal distribution of fibril radii that has been widely reported within tendon tissues. Tensile strain applied to our model fibrils straightens the average fibrillar twist and flattens the D-band modulation. Our PFC approach should apply directly to other longitudinally-modulated chiral filaments, such as fibrin and intermediate filaments.

show abstract

The Collagen Suprafamily: From Biosynthesis to Advanced Biomaterial Development

et al. 2018

View full text Add to dashboard Cite

Collagen is the oldest and most abundant extracellular matrix protein that has found many applications in food, cosmetic, pharmaceutical, and biomedical industries. First, an overview of the family of collagens and their respective structures, conformation, and biosynthesis is provided. The advances and shortfalls of various collagen preparations (e.g., mammalian/marine extracted collagen, cell‐produced collagens, recombinant collagens, and collagen‐like peptides) and crosslinking technologies (e.g., chemical, physical, and biological) are then critically discussed. Subsequently, an array of structural, thermal, mechanical, biochemical, and biological assays is examined, which are developed to analyze and characterize collagenous structures. Lastly, a comprehensive review is provided on how advances in engineering, chemistry, and biology have enabled the development of bioactive, 3D structures (e.g., tissue grafts, biomaterials, cell‐assembled tissue equivalents) that closely imitate native supramolecular assemblies and have the capacity to deliver in a localized and sustained manner viable cell populations and/or bioactive/therapeutic molecules. Clearly, collagens have a long history in both evolution and biotechnology and continue to offer both challenges and exciting opportunities in regenerative medicine as nature's biomaterial of choice.

show abstract

Not only tendons: The other architecture of collagen fibrils

Cited by 23 publications

References 56 publications

Polymorphism of stable collagen fibrils

Polymorphism of stable collagen fibrils

Phase-field collagen fibrils: Coupling chirality and density modulations

The Collagen Suprafamily: From Biosynthesis to Advanced Biomaterial Development

Contact Info

Product

Resources

About