Carbon nanotubes increase the electrical conductivity of fibroblast-seeded collagen hydrogels

Rebecca A. MacDonald, Christopher M. Voge, Mihalis Kariolis, Jan P. Stegemann

Research output: Contribution to journalArticlepeer-review

113 Scopus citations


Carbon nanotubes are attractive as additives in fiber-reinforced composites due to their high aspect ratio, strength and electrical conductivity. In the present study, solubilized collagen Type I was polymerized in the presence of dispersed single-walled carbon nanotubes (SWNT) and human dermal fibroblast cells (HDF) to produce collagen-SWNT composite biomaterials with HDF embedded directly in the matrix. The resulting constructs, with SWNT loadings of 0 (control), 0.8, 2.0 and 4.0 wt.% SWNT, were cultured and electrical properties were evaluated in the frequency range 5-500 kHz at days 3 and 7. All collagen-SWNT hydrogel matrices underwent HDF-mediated gel compaction over time in culture, but the presence of SWNT significantly decreased the rate and extent of gel compaction. Viability of HDF in all constructs was consistently high and cell morphology was not affected by the presence of SWNT. However, cell number at day 7 in culture decreased with increasing SWNT loading. Electrical conductivity of the constructs varied from 3 to 7 mS cm-1, depending on SWNT loading level. Conductivity increased uniformly with increasing wt.% of SWNT (R = 0.78) and showed a modest frequency dependence, suggesting that the electrical percolation threshold had not been reached in these materials. These data demonstrate that the electrical conductivity of cell-seeded collagen gels can be increased through the incorporation of carbon nanotubes. Protein-SWNT composite materials may have application as scaffolds for tissue engineering, as substrates to study electrical stimulation of cells, and as transducers or leads for biosensors.

Original languageEnglish (US)
Pages (from-to)1583-1592
Number of pages10
JournalActa Biomaterialia
Issue number6
StatePublished - Nov 2008
Externally publishedYes


  • Collagen Type I
  • Composites
  • Electrical conductivity
  • Fibroblasts
  • Single-walled nanotubes

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Biochemistry
  • Biomedical Engineering
  • Molecular Biology


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