Molecularly resolved images of peptide-functionalized gold surfaces by scanning tunneling microscopy.

Department of Chemistry and Biochemistry, Center for Nano- and Molecular Science and Technology, and Institute for Cell and Molecular Biology, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712, USA.

Journal of the American Chemical Society 2012 Nov 28

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Peptide-terminated monolayers were formed through a Huisgen cycloaddition reaction between an α-helical peptide containing two propargylglycine unnatural functional groups 20 Å apart and an alkanethiol self-assembled monolayer (SAM) on a gold surface containing 25% surface density of reactive azide terminal groups. The azide- and peptide-terminated surfaces were imaged by scanning tunneling microscopy (STM) using a low tunneling current of 10 pA. On the peptide-terminated surface, oblong features ~30 Å long and ~20 Å wide were observed and attributed to individual surface-bound α-helical peptides oriented parallel to the gold surface. These features covered an area of the surface corresponding to a density of 0.11 ± 0.01 peptides nm(-2), compared with a theoretical density of ~0.14 peptides nm(-2) for a fully reacted surface. Finally, no evidence of peptide aggregation was observed on either short (<10 nm) or long (~100 nm) length scales.

Citation

Annette F Raigoza, Lauren J Webb. Molecularly resolved images of peptide-functionalized gold surfaces by scanning tunneling microscopy. Journal of the American Chemical Society. 2012 Nov 28;134(47):19354-7