pH effects on BSA-dispersed carbon nanotubes studied by spectroscopy-enhanced composition evaluation techniques

Anal Chem. 2008 Jun 1;80(11):4049-54. doi: 10.1021/ac800124x. Epub 2008 May 7.

Abstract

Dispersion and exfoliation of carbon nanotubes (CNT) by water soluble dispersants such as surfactant, polymer or protein is a key step toward the application of carbon nanotubes in composite materials, biochemical and biomedical applications. Upon dispersion, the solution phase separates into dispersed nanotubes in the supernatant and a precipitate phase including carbonaceous impurities but also nanotubes and dispersants. Yet, simple but accurate tools for measuring the concentrations of the constituents are not available. In most studies a comparison between CNT suspensions is based on ocular observation or on UV-visible measurement of a featureless spectrum at single wavelength. Such measurements are complex since both nanotubes and most dispersants absorb along the whole UV-visible spectrum and an overlap of their signals occurs. In this paper we employ chemometric techniques to evaluate the pH effect on the concentration of both dispersant (protein-bovine serum albumin, BSA) and single-wall nanotube (SWNT) from a full UV-visible spectrum of aqueous solutions. We find strong correlation between the conformation of the protein and its dispersion efficiency.

MeSH terms

  • Animals
  • Calibration
  • Cattle
  • Hydrogen-Ion Concentration
  • Nanotubes, Carbon / chemistry*
  • Protein Conformation
  • Serum Albumin, Bovine / chemistry*
  • Spectrophotometry, Ultraviolet

Substances

  • Nanotubes, Carbon
  • Serum Albumin, Bovine