An AC electrokinetic method for enhanced detection of DNA nanoparticles

Rajaram Krishnan, Michael J. Heller

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


In biomedical research and diagnostics it is a challenge to isolate and detect low levels of nanoparticles and nanoscale biomarkers in blood and other biological samples. While highly sensitive epifluorescent microscope systems are available for ultra low level detection, the isolation of the specific entities from large sample volumes is often the bigger limitation. AC electrokinetic techniques like dielectrophoresis (DEP) offer an attractive mechanism for specifically concentrating nanoparticles into microscopic locations. Unfortunately, DEP requires significant sample dilution thus making the technology unsuitable for biological applications. Using a microelectrode array device, special conditions have been found for the separation of hmw-DNA and nanoparticles under high conductance (ionic strength) conditions. At AC frequencies in the 3000-10 000 Hz range, 10 μm microspheres and human T lymphocytes can be isolated into the DEP low field regions, while hmw-DNA and nanoparticles can be concentrated into microscopic high field regions for subsequent detection using an epifluorescent system.

Original languageEnglish (US)
Pages (from-to)253-261
Number of pages9
JournalJournal of Biophotonics
Issue number4
StatePublished - Apr 2009
Externally publishedYes


  • AC electrokinetics
  • DNA
  • Detection
  • Dielectrophoresis
  • Nanoparticles

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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