19F Magnetic Resonance Imaging Signals from Peptide Amphiphile Nanostructures Are Strongly Affected by Their Shape

Adam T. Preslar, Faifan Tantakitti, Kitae Park, Shanrong Zhang, Samuel I. Stupp, Thomas J. Meade

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Magnetic resonance imaging (MRI) is a noninvasive imaging modality that provides excellent spatial and temporal resolution. The most commonly used MR probes face significant challenges originating from the endogenous 1H background signal of water. In contrast, fluorine MRI (19F MRI) allows quantitative probe imaging with zero background signal. Probes with high fluorine content are required for high sensitivity, suggesting nanoscale supramolecular assemblies containing 19F probes offer a potentially useful strategy for optimum imaging as a result of improved payload. We report here on supramolecular nanostructures formed by fluorinated peptide amphiphiles containing either glutamic acid or lysine residues in their sequence. We identified molecules that form aggregates in water which transition from cylindrical to ribbon-like shape as pH increased from 4.5 to 8.0. Interestingly, we found that ribbon-like nanostructures had reduced magnetic resonance signal, whereas their cylindrical counterparts exhibited strong signals. We attribute this drastic difference to the greater mobility of fluorinated tails in the hydrophobic compartment of cylindrical nanostructures compared to lower mobility in ribbon-like assemblies. This discovery identifies a strategy to design supramolecular, self-assembling contrast agents for 19F MRI that can spatially map physiologically relevant changes in pH using changes in morphology.

Original languageEnglish
Pages (from-to)7376-7384
Number of pages9
JournalACS nano
Volume10
Issue number8
DOIs
Publication statusPublished - Aug 23 2016

Keywords

  • fluorine
  • fluorous
  • magnetic resonance imaging (MRI)
  • nanofiber
  • pH response
  • peptide amphiphile
  • self-assembly

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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