High-performance graphene-titania platform for detection of phosphopeptides in cancer cells

Anal Chem. 2012 Aug 7;84(15):6693-700. doi: 10.1021/ac301119r. Epub 2012 Jul 26.

Abstract

Phosphopeptides play a crucial role in many biological processes and constitute some of the most powerful biomarkers in disease detection. However they are often present in very low concentration, which makes their detection highly challenging. Here, we demonstrate the use of a solution-dispersible graphene-titania platform for the selective extraction of phosphopeptides from peptide mixtures. This is followed by direct analysis by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). The efficient charge and energy exchange between graphene and TiO(2) during laser irradiation in SELDI-TOF MS promotes the soft ionization of analytes and affords a detection limit in the attomole range, which is 10(2)-10(5) more sensitive than conventional platforms. The graphene-titania platform can also be used for detecting phosphopeptides in cancer cells (HeLa cells), where it shows high specificity (94%). An expanded library of 967 unique phosphopeptides is detected using significantly reduced loading of extraction matrixes compared to conventional TiO(2) bead-based assays.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Computational Biology
  • Graphite / chemistry*
  • HeLa Cells
  • Humans
  • Isoelectric Point
  • Nanotechnology
  • Phosphopeptides / analysis*
  • Solutions / chemistry
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization*
  • Titanium / chemistry*
  • Trypsin / metabolism

Substances

  • Phosphopeptides
  • Solutions
  • titanium dioxide
  • Graphite
  • Titanium
  • Trypsin