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Arrested dynamics in a model peptide hydrogel system

Rüter, Axel LU ; Kuczera, Stefan LU ; Gentile, Luigi LU and Olsson, Ulf LU (2020) In Soft Matter 16(11). p.2642-2651
Abstract

We report here on a peptide hydrogel system, which in contrast to most other such systems, is made up of relatively short fibrillar aggregates, discussing resemblance with colloidal rods. The synthetic model peptides A8K and A10K, where A denotes alanine and K lysine, self-assemble in aqueous solutions into ribbon-like aggregates having an average length 〈L〉 on the order of 100 nm and with a diameter d ≈ 6 nm. The aggregates can be seen as weakly charged rigid rods and they undergo an isotropic to nematic phase transition at higher concentrations. Translational motion perpendicular to the rod axis gets strongly hindered when the concentration is increased above the overlap concentration. Similarly, the rotational... (More)

We report here on a peptide hydrogel system, which in contrast to most other such systems, is made up of relatively short fibrillar aggregates, discussing resemblance with colloidal rods. The synthetic model peptides A8K and A10K, where A denotes alanine and K lysine, self-assemble in aqueous solutions into ribbon-like aggregates having an average length 〈L〉 on the order of 100 nm and with a diameter d ≈ 6 nm. The aggregates can be seen as weakly charged rigid rods and they undergo an isotropic to nematic phase transition at higher concentrations. Translational motion perpendicular to the rod axis gets strongly hindered when the concentration is increased above the overlap concentration. Similarly, the rotational motion is hindered, leading to very long stress relaxation times. The peptide self-assembly is driven by hydrophobic interactions and due to a net peptide charge the system is colloidally stable. However, at the same time short range, presumably hydrophobic, attractive interactions appear to affect the rheology of the system. Upon screening the long range electrostatic repulsion, with the addition of salt, the hydrophobic attraction becomes more dominant and we observe a transition from a repulsive glassy state to an attractive gel-state of the rod-like peptide aggregates.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Soft Matter
volume
16
issue
11
pages
10 pages
publisher
Royal Society of Chemistry
external identifiers
  • pmid:32119019
  • scopus:85082095984
ISSN
1744-683X
DOI
10.1039/c9sm02244a
language
English
LU publication?
yes
id
ad5cf431-c610-432e-b426-777789c2719e
date added to LUP
2020-04-03 10:54:00
date last changed
2020-10-20 02:03:47
@article{ad5cf431-c610-432e-b426-777789c2719e,
  abstract     = {<p>We report here on a peptide hydrogel system, which in contrast to most other such systems, is made up of relatively short fibrillar aggregates, discussing resemblance with colloidal rods. The synthetic model peptides A<sub>8</sub>K and A<sub>10</sub>K, where A denotes alanine and K lysine, self-assemble in aqueous solutions into ribbon-like aggregates having an average length 〈L〉 on the order of 100 nm and with a diameter d ≈ 6 nm. The aggregates can be seen as weakly charged rigid rods and they undergo an isotropic to nematic phase transition at higher concentrations. Translational motion perpendicular to the rod axis gets strongly hindered when the concentration is increased above the overlap concentration. Similarly, the rotational motion is hindered, leading to very long stress relaxation times. The peptide self-assembly is driven by hydrophobic interactions and due to a net peptide charge the system is colloidally stable. However, at the same time short range, presumably hydrophobic, attractive interactions appear to affect the rheology of the system. Upon screening the long range electrostatic repulsion, with the addition of salt, the hydrophobic attraction becomes more dominant and we observe a transition from a repulsive glassy state to an attractive gel-state of the rod-like peptide aggregates.</p>},
  author       = {Rüter, Axel and Kuczera, Stefan and Gentile, Luigi and Olsson, Ulf},
  issn         = {1744-683X},
  language     = {eng},
  number       = {11},
  pages        = {2642--2651},
  publisher    = {Royal Society of Chemistry},
  series       = {Soft Matter},
  title        = {Arrested dynamics in a model peptide hydrogel system},
  url          = {http://dx.doi.org/10.1039/c9sm02244a},
  doi          = {10.1039/c9sm02244a},
  volume       = {16},
  year         = {2020},
}