Morpholino monolayers

Preparation and label-free DNA analysis by surface hybridization

Napoleon Tercero, Kang Wang, Ping Gong, Rastislav Levicky

Research output: Contribution to journalArticle

Abstract

Surface hybridization, a reaction in which nucleic acid molecules in solution react with nucleic acid partners immobilized on a surface, is widely practiced in life science research. In these applications the immobilized partner, or "probe", is typically single-stranded DNA. Because DNA is strongly charged, high salt conditions are required to enable binding between analyte nucleic acids ("targets") in solution and the DNA probes. High salt, however, compromises prospects for label-free monitoring or control of the hybridization reaction through surface electric fields; it also stabilizes secondary structure in target species that can interfere with probe-target recognition. In this work, initial steps toward addressing these challenges are taken by introducing morpholinos, a class of uncharged DNA analogues, for surface-hybridization applications. Monolayers of morpholino probes on gold supports can be fabricated with methods similar to those employed with DNA and are shown to hybridize efficiently and sequence-specifically with target strands. Hybridization-induced changes in the interfacial charge organization are analyzed with electrochemical methods and compared for morpholino and DNA probe monolayers. Molecular mechanisms connecting surface hybridization state to the interfacial capacitance are identified and interpreted through comparison to numerical Poisson-Boltzmann calculations. Interestingly, positive as well as negative capacitive responses (contrast inversion) to hybridization are possible, depending on surface populations of mobile ions as controlled by the applied potential. Quantitative comparison of surface capacitance with target coverage (targets/area) reveals a nearly linear relationship and demonstrates sensitivities (limits of quantification) in the picogram per square millimeter range.

Original languageEnglish (US)
Pages (from-to)4953-4961
Number of pages9
JournalJournal of the American Chemical Society
Volume131
Issue number13
DOIs
StatePublished - Apr 8 2009

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Morpholinos
Labels
Monolayers
DNA
DNA Probes
Nucleic Acids
Nucleic acids
Salts
Immobilized Nucleic Acids
Biological Science Disciplines
Single-Stranded DNA
Gold
Capacitance
Ions
Surface states
Research
Population
Electric fields
Molecules
Monitoring

ASJC Scopus subject areas

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

Cite this

Morpholino monolayers : Preparation and label-free DNA analysis by surface hybridization. / Tercero, Napoleon; Wang, Kang; Gong, Ping; Levicky, Rastislav.

In: Journal of the American Chemical Society, Vol. 131, No. 13, 08.04.2009, p. 4953-4961.

Research output: Contribution to journalArticle

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