Single-molecule tracing on a fluidic microchip for quantitative detection of low-abundance nucleic acids

Tza Huei Wang, Yahui Peng, Chunyang Zhang, Kin Wong Pak, Chih Ming Ho

Research output: Contribution to journalArticle

109 Scopus citations


Here, we report a method capable of quantitative detection of low-abundance DNA/RNA molecules by incorporating confocal fluorescence spectroscopy, molecular beacons, and a molecular-confinement microfluidic reactor. By using a combination of ac and dc fields via a trio of 3-D electrodes in the microreactor, we are able to precisely direct the transport of individual molecules to a minuscule laser-focused detection volume (∼1 fL). A burst of fluorescence photons is detected whenever a molecular beacon-target hybrid flows through the detection region, and the amount of targets can be directly quantified according to the number of recorded single-molecule flow-through events. This assay consumes only attomoles of molecular probes and is able to quantitatively detect subpicomolar DNA targets. A measurement time of less than 2 min is sufficient to complete the detection.

Original languageEnglish (US)
Pages (from-to)5354-5359
Number of pages6
JournalJournal of the American Chemical Society
Issue number15
StatePublished - Apr 20 2005


ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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