Graphene oxide as a quencher for fluorescent assay of amino acids, peptides, and proteins

ACS Appl Mater Interfaces. 2012 Dec;4(12):7069-75. doi: 10.1021/am302704a. Epub 2012 Dec 3.

Abstract

Understanding the interaction between graphene oxide (GO) and the biomolecules is fundamentally essential, especially for disease- and drug-related peptides and proteins. In this study, GO was found to strongly interact with amino acids (tryptophan and tyrosine), peptides (Alzheimer's disease related amyloid beta 1-40 and type 2 diabetes related human islet amyloid polypeptide), and proteins (drug-related bovine and human serum albumin) by fluorescence quenching, indicating GO was a universal quencher for tryptophan or tyrosine related peptides and proteins. The quenching mechanism between GO and tryptophan (Trp) or tyrosine (Tyr) was determined as mainly static quenching, combined with dynamic quenching (Förster resonance energy transfer). Different quenching efficiency between GO and Trp or Tyr at different pHs indicated the importance of electrostatic interaction during quenching. Hydrophobic interaction also participated in quenching, which was proved by the presence of nonionic amphiphilic copolymer Pluronic F127 (PF127) in GO dispersion. The strong hydrophobic interaction between GO and PF127 efficiently blocked the hydrophobic interaction between GO and Trp or Tyr, lowering the quenching efficiency.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acids / analysis*
  • Graphite / chemistry*
  • Microscopy, Atomic Force
  • Oxides / chemistry*
  • Peptides / analysis*
  • Proteins / analysis*
  • Spectrometry, Fluorescence / methods*
  • Spectrophotometry, Ultraviolet

Substances

  • Amino Acids
  • Oxides
  • Peptides
  • Proteins
  • Graphite