title: Scanning tunnelling microscopic images of amino acids.
abstract: We present images of amino acids adsorbed on highly orientated pyrolytic graphite (HOPG) obtained with the scanning tunnelling microscope (STM) in air. Individual molecules can be observed although the majority of adsorbates appear to form clusters. In the case of leucine, methionine, and tryptophan, two molecules often associate together to form a dimer. Single or dimer glycine molecules were not seen, but a cluster of a number of them was observed. The various adsorbed states may be related to the different interactions between the amino acids and the graphite surface. The mechanism of image formation of the amino acids is probably related to charge transfer mechanisms.
authors.affiliation: Department of Bioengineering, University of Utah, Salt Lake 84112.
authors.forename: L
authors.initials: L
authors.lastname: Feng
authors.forename: C Z
authors.initials: CZ
authors.lastname: Hu
authors.forename: J D
authors.initials: JD
authors.lastname: Andrade
mesh_terms: D000327:Adsorption; D000596:Amino Acids; D005998:Glycine; D007930:Leucine; D008715:Methionine; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D014364:Tryptophan
chemical_list: D000596:Amino Acids; D014364:Tryptophan; D008715:Methionine; D007930:Leucine; D005998:Glycine