Immobilization of nucleic acids at solid surfaces: Effect of oligonucleotide length on layer assembly

A. B. Steel, R. L. Levicky, T. M. Herne, M. J. Tarlov

Research output: Contribution to journalArticlepeer-review


This report investigates the effect of DNA length and the presence of an anchoring group on the assembly of presynthesized oligonucteotides at a gold surface. The work seeks to advance fundamental insight into issues that impact the structure and behavior of surface-immobilized DNA layers, as in, for instance, DNA microarray and biosensor devices. The present study contrasts immobilization of single-stranded DNA (ssDNA) containing a terminal, 5' hexanethiol anchoring group with that of unfunctionalized oligonucleotides for lengths from 8 to 48 bases. Qualitatively, the results indicate that the thiol anchoring group strongly enhances oligonucleotide immobilization, but that the enhancement is reduced for longer strand lengths. Interestingly, examination of the probe coverage as a function of strand length suggests that adsorbed thiol-ssDNA oligonucleotides shorter than 24 bases tend to organize in end-tethered, highly extended configurations for which the long-term surface coverage is largely independent of oligonucleotide length. For strands longer than 24 bases, the surface coverage begins to decrease notably with probe length. The decrease is consistent with a less ordered arrangement of the DNA chains, presumably reflecting increasingly polymeric behavior.

Original languageEnglish (US)
Pages (from-to)975-981
Number of pages7
JournalBiophysical journal
Issue number2
StatePublished - 2000

ASJC Scopus subject areas

  • Biophysics


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