High-Curvature Nanostructuring Enhances Probe Display for Biomolecular Detection

Phil De Luna, Sahar S. Mahshid, Jagotamoy Das, Binquan Luan, Edward H. Sargent, Shana O. Kelley*, Ruhong Zhou

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

66 Scopus citations

Abstract

High-curvature electrodes facilitate rapid and sensitive detection of a broad class of molecular analytes. These sensors have reached detection limits not attained using bulk macroscale materials. It has been proposed that immobilized DNA probes are displayed at a high deflection angle on the sensor surface, which allows greater accessibility and more efficient hybridization. Here we report the first use of all-atom molecular dynamics simulations coupled with electrochemical experiments to explore the dynamics of single-stranded DNA immobilized on high-curvature versus flat surfaces. We find that high-curvature structures suppress DNA probe aggregation among adjacent probes. This results in conformations that are more freely accessed by target molecules. The effect observed is amplified in the presence of highly charged cations commonly used in electrochemical biosensing. The results of the simulations agree with experiments that measure the degree of hybridization in the presence of mono-, di-, and trivalent cations. On high-curvature structures, hybridization current density increases as positive charge increases, whereas on flat electrodes, the trivalent cations cause aggregation due to electrostatic overscreening, which leads to decreased current density and less sensitive detection.

Original languageEnglish (US)
Pages (from-to)1289-1295
Number of pages7
JournalNano letters
Volume17
Issue number2
DOIs
StatePublished - Feb 8 2017

Keywords

  • DNA hybridization
  • Molecular dynamics
  • biosensing
  • high-curvature effects
  • nanostructured microelectrodes

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering

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