Photodynamic control of bioactivity in a nanofiber matrix

Shantanu Sur, John B. Matson, Matthew J. Webber, Christina J. Newcomb, Samuel I. Stupp

Research output: Contribution to journalArticlepeer-review

63 Citations (Scopus)


Self-assembling peptide materials have been used extensively to mimic natural extracellular matrices (ECMs) by presenting bioactive epitopes on a synthetic matrix. Although this approach can facilitate a desired response from cells grown in the matrix, it lacks the capacity for spatial or temporal regulation of the presented signals. We describe here a photoresponsive, synthetic ECM using a supramolecular platform composed of peptide amphiphiles (PAs) that self-assemble into cylindrical nanofibers. A photocleavable nitrobenzyl ester group was included in the peptide backbone using a novel Fmoc-amino acid that is compatible with microwave-assisted solid-phase peptide synthesis. The placement of the photolabile group on the peptide backbone enabled efficient removal of the ECM-derived cell adhesion epitope RGDS from PA molecules upon exposure to light (half-life of photolysis ∼1.9 min) without affecting the nanofiber assembly. Fibroblasts cultured on RGDS-presenting PA nanofiber substrates demonstrated increased cell spreading and more mature focal adhesions compared with unfunctionalized and control (RGES-presenting) surfaces, as determined by immunostaining and cell morphological analysis. Furthermore, we observed an arrest in fibroblast spreading on substrates containing a cleavable RGDS epitope when the culture was exposed to light; in contrast, this dynamic shift in cell response was absent when the RGDS epitope was attached to the PA molecule by a light-insensitive control linker. Light-responsive bioactive materials can contribute to the development of synthetic systems that more closely mimic the dynamic nature of native ECM.

Original languageEnglish
Pages (from-to)10776-10785
Number of pages10
JournalACS nano
Issue number12
Publication statusPublished - Dec 21 2012


  • RGDS epitope
  • cell morphological analysis
  • nitrobenzyl
  • photodegradable
  • projected cell area
  • supramolecular nanofibers

ASJC Scopus subject areas

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

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