Dual-Signal Electrochemical Enantiospecific Recognition System via Competitive Supramolecular Host-Guest Interactions: The Case of Phenylalanine

Anal Chem. 2019 Feb 19;91(4):2908-2915. doi: 10.1021/acs.analchem.8b05047. Epub 2019 Jan 31.

Abstract

For developing highly selective and sensitive electrochemical sensors for chiral recognition, taking advantage of the synthetical properties of β-cyclodextrin (β-CD, strong host-guest recognition) and carbon nanotubes wrapped with reduced graphene oxide (CNTs@rGO, excellent electrochemical property and large surface area), as well as the differences in binding affinity between β-CD and guest molecules, a dual signal electrochemical sensing strategy was proposed herein for the first time in chiral recognition based on the competitive host-guest interaction between probe and chiral isomers with β-CD/CNTs@rGO. As a model system, rhodamine B (RhB) and phenylalanine enantiomers (d- and l-Phe) were introduced as probe and target enantiomers, respectively. Due to the host-guest interactions, RhB can enter into the β-CD cavity, showing remarkable oxidation peak current of RhB. In the presence of l-Phe, competitive interaction with the β-CD cavity occurs and RhB are replaced by l-Phe owing to the stronger binding affinity between l-Phe and β-CD, which results in the peak current of RhB decreasing and the peak current of l-Phe appears, and interestingly, the changes of both signals linearly correlate with the concentration of l-Phe. As for d-Phe, it cannot replace RhB owing to the weaker binding affinity between d-Phe and β-CD. Based on this, a dual-signal electrochemical sensor was developed successfully for recognizing Phe. This dual-signal sensing strategy can provide highly selective and sensitive recognition compared to single-signal sensor and has important potential applications in chiral recognition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Fluorescent Dyes / analysis
  • Graphite / chemistry*
  • Nanotubes, Carbon / chemistry*
  • Phenylalanine / analysis*
  • Rhodamines / analysis
  • Stereoisomerism
  • beta-Cyclodextrins / chemistry*

Substances

  • Fluorescent Dyes
  • Nanotubes, Carbon
  • Rhodamines
  • beta-Cyclodextrins
  • graphene oxide
  • Phenylalanine
  • Graphite
  • betadex
  • rhodamine B