Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2608.19810

A Central Disulfide Junction Drives Transient Network Formation in Elastin-Like Polypeptides, Enabling Low-Concentration Hydrogels

Tingting Zhang·Jean-François Le Meins·Jean-Paul Chapel·Saron Catak·Guillaume Goudounet·Olivier Sandre·Nadia Mahmoudi·Christophe Schatz·Bertrand Garbay
View original source ↗Read source document ↗Export metadata ↓

Abstract

The self-assembly of associative triblock copolymers composed of a central hydrophilic elastin-like polypeptide (ELP) block and short fatty acid end groups (C16) was investigated in aqueous solution. In one system, the ELP contains 80 pentapeptide units (C16-80-C16), whereas in the other two C16-ELP40 chains were oxidatively coupled through their terminal cysteine residues to form a central disulfide bond, yielding C16-(40)2-C16. Despite their nearly identical molecular weights and compositions, the two polymers exhibit markedly different self-assembly behaviors. C16-80-C16 forms large hydrophobic aggregates that remain kinetically trapped and do not develop a dynamically connected network. In contrast, C16-(40)2-C16 forms very small associative nodes with an aggregation number of only $\sim$3 chains. These nodes coexist with larger clusters and become dynamically interconnected at higher concentrations, leading to transparent hydrogels at concentrations as low as 2.5 wt %. Oscillatory rheology reveals a transient Maxwell network governed by a single relaxation process associated with the reversible association of the C16 end groups. SAXS, light scattering, cryo-TEM, and molecular modeling consistently support a model in which the central disulfide junction promotes transient network formation.

Explore related subjects

cond-mat.soft

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Tingting Zhang, Jean-François Le Meins, Jean-Paul Chapel, Saron Catak, Guillaume Goudounet, Olivier Sandre, Nadia Mahmoudi, Christophe Schatz, Bertrand Garbay. 2026-08-20. A Central Disulfide Junction Drives Transient Network Formation in Elastin-Like Polypeptides, Enabling Low-Concentration Hydrogels. https://arxiv.org/abs/2608.19810

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Transient Elasticity -- A Unifying Framework for Thixotropy, Polymers, and Granular Media

Thixotropic yield stress fluids, such as paint or ketchup, are traditionally viewed as elastic structures that, under shear rates, break into viscous liquids with lumps, and reconnect at rest. An alternative framework is presented here: Upon shear, structural destruction is incomplete, leaving sufficient connections. As a result, elasticity fundamentally underlies their non-Newtonian behavior, though they do appear purely viscous under a steady shear, displaying little direct evidence of elastic rebound---same as granular media and polymers. Consequently, all three are described by the same set of evolution equations, differing only in their parameters. These equations are set up by starting from solid dynamics and allowing the elastic strain $\varepsilon^e$ to relax, which in effect interpolates between solid and fluid behavior, appropriate for systems that display both types of behavior. Incorporating in addition a two-temperature framework, tracking how energy is dissipated in two consecutive stages, yields the nonlinear model of Transient Elasticity (TE). It describes an elasticity that is transient in time yet persistent under shear. Previously validated for polymers and granular media, TE is here applied to thixotropic yield-stress fluids. As shown, it successfully accounts for a wide range of characteristic phenomena, including over- and undershoot, viscosity bifurcation, shear banding, and oscillatory rheography. Given its appropriateness across structurally diverse systems, TE offers a unified, surprisingly general account of non-Newtonian phenomena.

cond-mat.soft↗
arXiv2026

Deformation and organization of droplet-encapsulated soft beads

Many biological, culinary, and engineering processes lead to the co-encapsulation of several soft particles within a liquid interface. In these situations the particles are bound together by the capillary forces that deform them and influence their biological or rheological properties. Here, we introduce an experimental approach to encapsulate a controlled number of soft beads within aqueous droplets in oil. These droplet-encapsulated gels are manipulated in a deformable microfluidic device to merge them and modify the liquid fraction. In the dry limit the contact surface between the hydrogels is found to be determined by the elastocapillary number $E_c$, with the contact radius following a $E_c^{1/3}$ dependence, indicating that the deformation increases for soft or small particles. When multiple beads are co-encapsulated within a single droplet they can be arranged into linear or three-dimensional aggregates that remain at a local energy minimum.

cond-mat.soft↗
arXiv2026

Flexoelectricity-driven softening of bend elasticity leads to spontaneous chiral symmetry breaking in a polar fluid

The origin of the recently observed spontaneous chiral symmetry breaking in polar fluids composed of achiral molecules is an unsolved problem, raising fundamental questions about how heliconical structures emerge in such systems. Here, we investigate the pretransitional fluctuations leading to the formation of the spontaneously chiral twist-bend ferroelectric nematic phase using dielectric spectroscopy, light scattering, and small-angle X-ray scattering. We observe simultaneous softening of the bend elastic constant and the emergence of a collective dielectric mode on approaching the transition. By developing a theoretical model, we show that these phenomena are signatures of a flexoelectricity-driven transition arising from the coupling between electric polarization and bend deformation.

cond-mat.soft↗