Spermine-induced hybridization and charge inversion at the diffuse layer of a DNA-FET

Roberto De La Rica, Cesar Fernandez-Sanchez, Jimenez-Jorquera Cecilia, Antonio Baldi

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3 Citations (Scopus)


Detection of DNA hybridization events by using field-effect transducers is limited by the electrolyte content of the medium. So far, DNA was thought to hybridize only in solutions with concentrated electrolytes. In these media, the interface between the transducer gate and the solution is reduced to a thin layer in close contact with the surface, and DNA is poorly detected. In the present work, this limitation is overcome by using spermine as screening polycation. Hybridization assays with polycation concentrations as low as 10 mu M are reported. This ensures that hybridization takes place at the diffuse layer of the interface. The reported results suggest a charge-inversion mechanism induced by spermine. A target sequence is real-time label-free detected in the range from 10 to 500 nM.
Original languageEnglish
Pages (from-to)7614-7617
Number of pages4
JournalJournal of Physical Chemistry B
Issue number25
Early online date31 May 2008
Publication statusPublished - 26 Jun 2008


  • spermine-induced hybridization
  • charge inversion
  • diffuse layer

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