Paper BI-TuP18
STM Characterization of Chemically Prepared Peptide-Functionalized Monolayers

Tuesday, October 30, 2012, 6:00 pm, Room Central Hall

Proteins are able to express catalytic and sensing functions that current technologies are unable to reproduce. Instead, efforts have been focused on properly integrating this functionality with non-biological materials. Unfortunately, proteins are generally observed to lose function because of unfolding, aggregation, and overall loss of structure that occurs when a soft, solution-phase material is placed in the harsh structural and electrostatic environment that occurs on and near surfaces. To improve protein-surface interactions, we create a surface that is composed of peptides, which can be tailored for specific protein attachment. Here, we present scanning tunneling microscopy (STM) images of peptide-terminated monolayers on a gold surface created by functionalizing alkanethiol self-assembled monolayers. A Huisgen cycloaddition “click” reaction is used to tether the peptides to the surface at reactive locations that line up with modified residues on the peptide. STM is used to image the surface at each reaction step with molecular resolution. A complete surface reaction would generate a peptide density of approximately 0.6 peptides/nm², based on the distance between reactive azide functional groups and the theoretical size of our peptide. We estimate 0.4 peptides/nm² based on the area covered by peptides in our images.