Bundle Formation in Biomimetic Hydrogels

Abstract

Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and mechanical responsiveness through nonlinear mechanics, properties that are rarely observed in synthetic hydrogels. Using small-angle X-ray scattering (SAXS), we study the bundle formation and hydrogelation process of polyisocyanide gels, a synthetic material that uniquely mimics the structure and mechanics of biogels. We show how the structure of the material changes at the (thermally induced) gelation point and how factors such as concentration and polymer length determine the architecture, and with that, the mechanical properties. The correlation of the gel mechanics and the structural parameters obtained from SAXS experiments is essential in the design of future (synthetic) mimics of biopolymer networks.

Multi-scale assembly of hydrogels formed by highly branched arabinoxylans from Plantago ovata seed mucilage studied by USANS/SANS and rheology

“…In that work, we have established the link between hydrogen bonding and the degree of molecular association, which enabled us to formulate the hypothesis that the nature of gel formation may also depend on hydrogen bonding. That being said, the knowledge that hydrogen bonding drives molecular association is insufficient to predict the structure of gel assemblies, since gel formation may encompass or even require other structural transitions on the molecular (e.g., coil-helix (Schefer, Usov & Mezzenga, 2015)) and/or supra-molecular levels (e.g., bundle formation (Jaspers, Pape, Voets, Rowan, Portale & Kouwer, 2016)).…”

Controlling the gelation temperature of biomimetic polyisocyanides

“…The EG substituents render the aqueous polymer solutions thermoresponsive. Because of their rigid conformation and high molecular weight, the polymers do not precipitate, but rather form a network of bundled polymer chains that is capable of holding water over 10,000× its own weight [17]. The bundled structure of relatively stiff polymer chains causes the PIC gels to become much stiffer under stress [16,18].…”

Biomimetic Networks with Enhanced Photodynamic Antimicrobial Activity from Conjugated Polythiophene/Polyisocyanide Hybrid Hydrogels

“…By raising the temperature, part of PMNT is released from the complex. The PIC gelation itself results from the formation of a 3D network of bundled chains that assemble through hydrophobic interactions between the rigid helical polymer chains . PIC or PIC/PMNT gelation is readily monitored by measuring the storage modulus G ′ as a function of temperature (Figure e).…”