Tunable mechanics of peptide nanofiber gels

Megan A. Greenfield, Jessica R. Hoffman, Monica Olvera De La Cruz, Samuel I Stupp

Research output: Contribution to journalArticle

116 Citations (Scopus)

Abstract

The mechanical properties of self-assembled fibrillar networks are influenced by the specific intermolecular interactions that modulate fiber entanglements. We investigate how changing these interactions influences the mechanics of self-assembled nanofiber gels composed of peptide amphiphile (PA) molecules. PAs developed in our laboratory self-assemble into gels of nanofibers after neutralization or salt-mediated screening of the charged residues in their peptide segment. We report here on the gelation, stiffness, and response to deformation of gels formed from a negatively charged PA and HCl or CaCl 2. Scanning electron microscopy of these gels demonstrates a similar morphology, whereas the oscillatory Theological measurements indicate that the calcium-mediated ionic bridges in Cacl2-PA gels form stronger intra- and interfiber cross-links than the hydrogen bonds formed by the protonated carboxylic acid residues in HCl-PA gels. As a result, CaCl2-PA gels can withstand higher strains than HCl-PA gels. After exposure to a series of strain sweeps with increasing strain amplitude HCl- and CaCl2-PA gels both, recover 42% of their original stiffness. In contrast, after sustained deformation at 100% strain, HCl-PA gels recover nearly 90% of their original stiffness after 10 min, while the CaCl2-PA gels only recover 35%. This result suggests that the hydrogen bonds formed, by the protonated acids in the HCl-PA gels allow the gel to relax quickly to its initial state, while the strong calcium cross-links in the CaCl2- PA gels lock in the deformed structure and inhibit the gel's ability to recover. We also show that the rheological scaling behaviors of HCl- and CaCl2-PA gels are consistent with, that of uncross- and cross-linked semiflexible biopolymer networks, respectively. The ability to modify how self-assembled fibrillar networks respond to deformations is important in developing self-assembled gels that can resist and recover from the large deformations that these gels encounter while serving as synthetic cell scaffolds in vivo.

Original languageEnglish
Pages (from-to)3641-3647
Number of pages7
JournalLangmuir
Volume26
Issue number5
DOIs
Publication statusPublished - Mar 2 2010

Fingerprint

Nanofibers
Peptides
peptides
Mechanics
Amphiphiles
Gels
gels
stiffness
Stiffness
calcium
Calcium
Hydrogen bonds
hydrogen bonds
Biopolymers
biopolymers
gelation
Gelation
Carboxylic Acids
Carboxylic acids
Scaffolds

ASJC Scopus subject areas

  • Electrochemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Materials Science(all)
  • Spectroscopy

Cite this

Greenfield, M. A., Hoffman, J. R., De La Cruz, M. O., & Stupp, S. I. (2010). Tunable mechanics of peptide nanofiber gels. Langmuir, 26(5), 3641-3647. https://doi.org/10.1021/la9030969

Tunable mechanics of peptide nanofiber gels. / Greenfield, Megan A.; Hoffman, Jessica R.; De La Cruz, Monica Olvera; Stupp, Samuel I.

In: Langmuir, Vol. 26, No. 5, 02.03.2010, p. 3641-3647.

Research output: Contribution to journalArticle

Greenfield, MA, Hoffman, JR, De La Cruz, MO & Stupp, SI 2010, 'Tunable mechanics of peptide nanofiber gels', Langmuir, vol. 26, no. 5, pp. 3641-3647. https://doi.org/10.1021/la9030969
Greenfield MA, Hoffman JR, De La Cruz MO, Stupp SI. Tunable mechanics of peptide nanofiber gels. Langmuir. 2010 Mar 2;26(5):3641-3647. https://doi.org/10.1021/la9030969
Greenfield, Megan A. ; Hoffman, Jessica R. ; De La Cruz, Monica Olvera ; Stupp, Samuel I. / Tunable mechanics of peptide nanofiber gels. In: Langmuir. 2010 ; Vol. 26, No. 5. pp. 3641-3647.
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