Strain-Stiffening of Agarose Gels

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2019-06-18
Major/Subject
Mcode
Degree programme
Language
en
Pages
6
670-675
Series
ACS Macro Letters, Volume 2019, issue 8
Abstract
Strain-stiffening is one of the characteristic properties of biological hydrogels and extracellular matrices, where the stiffness increases upon increased deformation. Whereas strain-stiffening is ubiquitous in protein-based materials, it has been less observed for polysaccharide and synthetic polymer gels. Here we show that agarose, that is, a common linear polysaccharide, forms helical fibrillar bundles upon cooling from aqueous solution. The hydrogels with these semiflexible fibrils show pronounced strain-stiffening. However, to reveal strain-stiffening, suppressing wall slippage turned as untrivial. Upon exploring different sample preparation techniques and rheological architectures, the cross-hatched parallel plate geometries and in situ gelation in the rheometer successfully prevented the slippage and resolved the strain-stiffening behavior. Combining with microscopy, we conclude that strain-stiffening is due to the semiflexible nature of the agarose fibrils and their geometrical connectivity, which is below the central-force isostatic critical connectivity. The biocompatibility and the observed strain-stiffening suggest the potential of agarose hydrogels in biomedical applications.
Description
| openaire: EC/H2020/742829/EU//DRIVEN
Keywords
NEGATIVE NORMAL STRESS, NONLINEAR ELASTICITY, WALL SLIP, MECHANICAL-PROPERTIES, HYDROGELS, NETWORKS, ELASTOMERS
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Citation
Bertula, K, Martikainen, L, Munne, P M, Hietala, S, Klefström, J, Ikkala, O & Nonappa, N 2019, ' Strain-Stiffening of Agarose Gels ', ACS Macro Letters, vol. 8, no. 6, pp. 670-675 . https://doi.org/10.1021/acsmacrolett.9b00258