High-Resolution X-Ray Photoelectron Spectroscopy of Mixed Silane Monolayers for DNA Attachment

Rebecca A. Shircliff, Ina T. Martin, Joel W. Pankow, John Fennell, Paul Stradins, Maria L. Ghirardi, Scott W. Cowley, Howard M. Branz

Research output: Contribution to journalArticlepeer-review

24 Scopus Citations


The amine density of 3-aminopropyldimethylethoxysilane (APDMES) films on silica is controlled to determine its effect on DNA probe density and subsequent DNA hybridization. The amine density is tailored by controlling the surface reaction time of (1) APDMES, or (2) n-propyldimethylchlorosilane (PDMCS, which is not amine terminated) and then reacting it with APDMES to form a mixed monolayer. High-resolution X-ray photoelectron spectroscopy (XPS) is used to quantify silane surface coverage of both pure and mixed monolayers on silica; the XPS data demonstrate control of amine density in both pure APDMES and PDMCS/APDMES mixed monolayers. A linear correlation between the atomic concentration of N atoms from the amine and Si atoms from the APDMES in pure APDMES films allows us to calculate the PDMCS/APDMES ratio in the mixed monolayers. Fluorescence from attached DNA probes and from hybridized DNA decreases as the percentage of APDMES in the mixed monolayer is decreased by dilution with PDMCS.

Original languageAmerican English
Pages (from-to)3285-3292
Number of pages8
JournalACS Applied Materials and Interfaces
Issue number9
StatePublished - 28 Sep 2011

NREL Publication Number

  • NREL/JA-5200-53364


  • DNA hybridization
  • DNA immobilization
  • mixed monolayer
  • Si 2p
  • silanes
  • XPS


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