Control of self-assembling oligopeptide matrix formation through systematic variation of amino acid sequence

Michael R. Caplan, Elissa M. Schwartzfarb, Shuguang Zhang, Roger D. Kamm, Douglas A. Lauffenburger

Research output: Contribution to journalArticle

196 Scopus citations

Abstract

In order to elucidate design principles for biocompatible materials that can be created by in situ transformation from self-assembling oligopeptides, we investigate a class of oligopeptides that can self-assemble in salt solutions to form three-dimensional matrices. This class of peptides possesses a repeated sequence of amino acid residues with the type: hydrophobic/negatively-charged/hydrophobic/positively-charged. We systematically vary three chief aspects of this sequence type: (1) the hydrophobic side chains; (2) the charged side-chains; and (3) the number of repeats. Employing a rheometric assay to judge matrix formation, we determine the critical concentration of NaCl salt solution required to drive transformation from viscous state to gel state. We find that increasing side-chain hydrophobicity decreases the critical salt concentration in accord with our previous validation of DLVO theory for explaining this self-assembly phenomenon Caplan et al. (Biomacromolecules 1 (2000) 627). Further, we find that increasing the number of repeats yields a biphasic dependence-first decreasing, then increasing, the critical salt concentration. We believe that this result is likely due to an unequal competition between a greater hydrophobic (favorable) effect and a greater entropic (unfavorable) effect as the peptide length is increased. Finally, we find that we can use this understanding to rationally alter the charged side-chains to create a self-assembling oligopeptide sequence that at pH 7 remains viscous in the absence of salt but gels in the presence of physiological salt concentrations, a highly useful property for technological applications.

Original languageEnglish (US)
Pages (from-to)219-227
Number of pages9
JournalBiomaterials
Volume23
Issue number1
DOIs
StatePublished - Jan 1 2002

Keywords

  • Amino acid sequence
  • Biomaterial
  • Oligopeptide
  • Self-assembly

ASJC Scopus subject areas

  • Bioengineering
  • Ceramics and Composites
  • Biophysics
  • Biomaterials
  • Mechanics of Materials

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    Caplan, M. R., Schwartzfarb, E. M., Zhang, S., Kamm, R. D., & Lauffenburger, D. A. (2002). Control of self-assembling oligopeptide matrix formation through systematic variation of amino acid sequence. Biomaterials, 23(1), 219-227. https://doi.org/10.1016/S0142-9612(01)00099-0