DNA sensors and aptasensors based on the hemin/G-quadruplex-controlled aggregation of Au NPs in the presence of L-cysteine

Angelica Niazov-Elkan, Eyal Golub, Etery Sharon, Dora Balogh, Itamar Willner

Research output: Contribution to journalArticlepeer-review

Abstract

L-cysteine induces the aggregation of Au nanoparticles (NPs), resulting in a color transition from red to blue due to interparticle plasmonic coupling in the aggregated structure. The hemin/G-quadruplex horseradish peroxidase-mimicking DNAzyme catalyzes the aerobic oxidation of L-cysteine to cystine, a process that inhibits the aggregation of the NPs. The degree of inhibition of the aggregation process is controlled by the concentration of the DNAzyme in the system. These functions are implemented to develop sensing platforms for the detection of a target DNA, for the analysis of aptamer-substrate complexes, and for the analysis of L-cysteine in human urine samples. A hairpin DNA structure that includes a recognition site for the DNA analyte and a caged G-quadruplex sequence, is opened in the presence of the target DNA. The resulting self-assembled hemin/G-quadruplex acts as catalyst that controls the aggregation of the Au NPs. Also, the thrombin-binding aptamer folds into a G-quadruplex nanostructure upon binding to thrombin. The association of hemin to the resulting G-quadruplex aptamer-thrombin complex leads to a catalytic label that controls the L-cysteine-mediated aggregation of the Au NPs. The hemin/G-qaudruplex-controlled aggregation of Au NPs process is further implemented for visual and spectroscopic detection of L-cysteine concentration in urine samples.

Original languageEnglish
Pages (from-to)2883-2891
Number of pages9
JournalSmall
Volume10
Issue number14
DOIs
StatePublished - 23 Jul 2014
Externally publishedYes

Keywords

  • aptamer
  • hairpin
  • nucleic acid
  • thiol
  • thrombin

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biomaterials
  • General Chemistry
  • General Materials Science

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