Response of biopolymer networks governed by the physical properties of cross-linking molecules

Wang, Xi; Zhu, Qian; Qian, Jin; Lin, Yuan; Shenoy, Vivek B.

doi:10.1039/c5sm02820e

Cited by 27 publications

(27 citation statements)

References 46 publications

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“…Also, the failure of individual polymers which involves breaking down complicated macromolecular structures [52], is much more complicated than the simple threshold we used. Both these effects make it more likely for the network to focus stress and crossover to crack nucleation in the thermodynamic limit [34,35]. The critical regime we found for p < p c may be observable in man-made materials in which bending stiffness and threshold are controlled to be very small.…”

mentioning

confidence: 89%

Fiber networks below the isostatic point: Fracture without stress concentration

Zhang

Rocklin

Sander

et al. 2017

Phys. Rev. Materials

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Crack nucleation is a ubiquitous phenomena during materials failure, because stress focuses on crack tips. It is known that exceptions to this general rule arise in the limit of strong disorder or vanishing mechanical stability, where stress distributes over a divergent length scale and the material displays diffusive damage. Here we show, using simulations, that a class of diluted lattices displays a new critical phase when they are below isostaticity, where stress never concentrates, damage always occurs over a divergent length scale, and catastrophic failure is avoided.

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mentioning

confidence: 89%

Fiber networks below the isostatic point: Fracture without stress concentration

Zhang

Rocklin

Sander

et al. 2017

Phys. Rev. Materials

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“…Considering natural biopolymer networks, the majority of studies have focused on reconstituted actin networks, crosslinked with different natural crosslinking proteins (Claessens et al, 2006;Schmoller et al, 2008;Schmoller et al, 2009;Lieleg et al, 2011) or synthetic crosslinking modules (Lorenz et al, 2018). These studies have shown that the crosslink properties (kinetics and stiffness) affect network topology, elastic modulus as well as stress relaxation and aging (Claessens et al, 2006;Schmoller et al, 2008;Schmoller et al, 2009;Lieleg et al, 2011;Strehle et al, 2011;Wei et al, 2016). Analogous studies aimed at understanding the effect of crosslink kinetics on viscoelastic material responses have been performed for a number of synthetic polymeric materials.…”

Section: Introductionmentioning

confidence: 99%

Influence of Network Topology on the Viscoelastic Properties of Dynamically Crosslinked Hydrogels

Grad¹,

Tunn²,

Voerman³

et al. 2020

Preprint

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Biological materials combine stress relaxation and self-healing with non-linear stress-strain responses. These characteristic features are a direct result of hierarchical self-assembly, which often results in fiber-like architectures. Even though structural knowledge is rapidly increasing, it has remained a challenge to establish relationships between microscopic and macroscopic structure and function. Here, we focus on understanding how network topology determines the viscoelastic properties, i.e. stress relaxation, of biomimetic hydrogels. We have dynamically crosslinked two different synthetic polymers with one and the same crosslink. The first polymer, a polyisocyanopeptide (PIC), self-assembles into semi-flexible, fiber-like bundles and thus displays stress-stiffening, similar to many biopolymer networks. The second polymer, 4-arm poly(ethylene glycol) (starPEG), serves as a reference network with well-characterized structural and viscoelastic properties. Using one and the same coiled coil crosslink allows us to decouple the effects of crosslink kinetics and network topology on the stress relaxation behavior of the resulting hydrogel networks. We show that the fiber-containing PIC network displays a relaxation time approximately two orders of magnitude slower than the starPEG network. This reveals that crosslink kinetics is not the only determinant for stress relaxation. Instead, we propose that the different network topologies determine the ability of elastically active network chains to relax stress. In the starPEG network, each elastically active chain contains exactly one crosslink. In the absence of entanglements, crosslink dissociation thus relaxes the entire chain. In contrast, each polymer is crosslinked to the fiber bundle in multiple positions in the PIC hydrogel. The dissociation of a single crosslink is thus not sufficient for chain relaxation. This suggests that tuning the number of crosslinks per elastically active chain in combination with crosslink kinetics is a powerful design principle for tuning stress relaxation in polymeric materials. The presence of a higher number of crosslinks per elastically active chain thus yields materials with a slow macroscopic relaxation time but fast dynamics at the microscopic level. Using this principle for the design of synthetic cell culture matrices will yield materials with excellent long-term stability combined with the ability to locally reorganize, thus facilitating cell motility, spreading and growth.

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“…Although the cross-linking proteins are very flexible 58 – 60 , their stabilizing effect by increasing the interpenetrating connectivity in the branched actin network is rather distinct. The branched actin network with a low density of cross-linking proteins is incapable of supporting the propulsion force for cell motility.…”

Section: Resultsmentioning

confidence: 99%

“…The diameters and elastic properties of actin filaments and cross-linking proteins are obtained from refs. 58 , 60 , 88 , 89 , as shown in Supplementary Table S1 .…”

Section: Methodsmentioning

confidence: 99%

Predictive assembling model reveals the self-adaptive elastic properties of lamellipodial actin networks for cell migration

et al. 2020

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Branched actin network supports cell migration through extracellular microenvironments. However, it is unknown how intracellular proteins adapt the elastic properties of the network to the highly varying extracellular resistance. Here we develop a three-dimensional assembling model to simulate the realistic self-assembling process of the network by encompassing intracellular proteins and their dynamic interactions. Combining this multiscale model with finite element method, we reveal that the network can not only sense the variation of extracellular resistance but also self-adapt its elastic properties through remodeling with intracellular proteins. Such resistance-adaptive elastic behaviours are versatile and essential in supporting cell migration through varying extracellular microenvironments. The bending deformation mechanism and anisotropic Poisson’s ratios determine why lamellipodia persistently evolve into sheet-like structures. Our predictions are confirmed by published experiments. The revealed self-adaptive elastic properties of the networks are also applicable to the endocytosis, phagocytosis, vesicle trafficking, intracellular pathogen transport and dendritic spine formation.

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Response of biopolymer networks governed by the physical properties of cross-linking molecules

Cited by 27 publications

References 46 publications

Fiber networks below the isostatic point: Fracture without stress concentration

Fiber networks below the isostatic point: Fracture without stress concentration

Influence of Network Topology on the Viscoelastic Properties of Dynamically Crosslinked Hydrogels

Predictive assembling model reveals the self-adaptive elastic properties of lamellipodial actin networks for cell migration

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