Highly cooperative behavior of peptide nucleic acid-linked DNA-modified gold-nanopartide and comb-polymer aggregates

Abigail K.R. Lytton-Jean, Julianne M. Gibbs-Davis, Hai Long, George C. Schatz, Chad A. Mirkin, Sonbinh T. Nguyen

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An experiment was conducted to show that peptide nucleic acid (PNA)-linked gold nanoparticles (AuNP)-DNA and polymer-DNA hybrid aggregates display sharp melting transitions when compared with unmodified PNA-DNA duplexes. The melting behavior of unmodified PNA:DNA duplexes of the same sequence were examined to create a basis for comparison. The duplexes of the same sequence display opposite Tm dependence on salt concentration. The presence of PNA-linked aggregates was indicated by a associated color change from red to blue, which arises from a dampening and shifting of the AuNP surface plasmon band. An unusual and general salt dependence of the melting temperature of PNA:DNA duplexes within a hybrid aggregate was recovered, which is the reverse of the trend observed in unmodified PNA:DNA duplexes. The closely spaced duplexes inside the aggregates leads to the positive salt-dependent behavior, which in turn, leads in cooperative interactions between neighboring duplexes.

Original languageEnglish
Pages (from-to)706-709
Number of pages4
JournalAdvanced Materials
Issue number6
Publication statusPublished - Feb 9 2009


ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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