Epitope topography controls bioactivity in supramolecular nanofibers

Shantanu Sur, Faifan Tantakitti, John B. Matson, Samuel I. Stupp*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Incorporating bioactivity into artificial scaffolds using peptide epitopes present in the extracellular matrix (ECM) is a well-known approach. A common strategy has involved epitopes that provide cells with attachment points and external cues through interaction with integrin receptors. Although a variety of bioactive sequences have been identified so far, less is known about their optimal display in a scaffold. We report here on the use of self-assembled peptide amphiphile (PA) nanofiber matrices to investigate the impact of spatial presentation of the fibronectin derived epitope RGDS on cell response. Using one, three, or five glycine residues, RGDS epitopes were systematically spaced out from the surface of the rigid nanofibers. We found that cell morphology was strongly affected by the separation of the epitope from the nanofiber surface, with the longest distance yielding the most cell-spreading, bundling of actin filaments, and a round-to-polygonal transformation of cell shape. Cell response to this type of epitope display was also accompanied with activated integrin-mediated signaling and formation of stronger adhesions between cells and substrate. Interestingly, unlike length, changing the molecular flexibility of the linker had minimal influence on cell behavior on the substrate for reasons that remain poorly understood. The use in this study of high persistence length nanofibers rather than common flexible polymers allows us to conclude that epitope topography at the nanoscale structure of a scaffold influences its bioactive properties independent of epitope density and mechanical properties. This journal is

Original languageEnglish (US)
Pages (from-to)520-532
Number of pages13
JournalBiomaterials Science
Issue number3
StatePublished - Mar 1 2015

ASJC Scopus subject areas

  • Biomedical Engineering
  • Materials Science(all)

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