Fluorescence detection of single-nucleotide polymorphisms using a thymidine-based molecular beacon

Chi Wei Liu, Yang Wei Lin, Chih Ching Huang, Huan Tsung Chang

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

We have developed a universal molecular beacon (T7-MB-T7) for the detection of single-nucleotide polymorphisms (SNPs). The beacon, which contains a 19-mer loop and a stem comprising a pair of seven thymidine (T) bases, forms double-stranded structures with target DNA molecules, leading to increases in the fluorescence of ethidium bromide (EthBr) as a result of intercalation. The interactions of the beacon with perfectly matched (DNApm) and single-base mismatched (DNAmm) DNA strands are stronger and weaker, respectively, than those with Hg2+ ions. As a result, the fluorescence of a solution containing T7-MB-T7, DNApm, EthBr, and Hg2+ is higher than that of a corresponding solution containing T7-MB-T7, DNAmm, EthBr, and Hg2+, because the former has a greater number of intercalation sites for EthBr. Under the optimal conditions (100 nM T7-MB-T7, 20 mM NaCl, 5.0 μM Hg2+, and 300 nM EthBr in 5.0 mM Tris-HCl solution, pH 7.4), the plot of the fluorescence intensity against the concentration of DNApm was linear over the range 5.0-100 nM (R2 = 0.98). A similar probe, T7-MBt-T7, is sensitive and selective for the detection of a gene associated with hereditary tyrosinemia type I. Relative to conventional MBs, our new probe offers the advantages of higher selectivity toward DNA, less nonspecific binding toward single-stranded-DNA-binding protein, greater resistance to nuclease digestion, and low cost; therefore, we suspect that this system holds great potential for practical studies of SNPs.

Original languageEnglish
Pages (from-to)2541-2546
Number of pages6
JournalBiosensors and Bioelectronics
Volume24
Issue number8
DOIs
Publication statusPublished - 2009 Apr 15

Fingerprint

Ethidium
Nucleotides
Polymorphism
Thymidine
Single Nucleotide Polymorphism
DNA
Fluorescence
Intercalation
Tyrosinemias
DNA-Binding Proteins
Genes
Digestion
Molecules
Ions
Costs and Cost Analysis
Costs

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

Cite this

Liu, Chi Wei ; Lin, Yang Wei ; Huang, Chih Ching ; Chang, Huan Tsung. / Fluorescence detection of single-nucleotide polymorphisms using a thymidine-based molecular beacon. In: Biosensors and Bioelectronics. 2009 ; Vol. 24, No. 8. pp. 2541-2546.
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Fluorescence detection of single-nucleotide polymorphisms using a thymidine-based molecular beacon. / Liu, Chi Wei; Lin, Yang Wei; Huang, Chih Ching; Chang, Huan Tsung.

In: Biosensors and Bioelectronics, Vol. 24, No. 8, 15.04.2009, p. 2541-2546.

Research output: Contribution to journalArticle

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