title: Nondestructive Raman and atomic force microscopy measurement of molecular structure for individual diphenylalanine nanotubes.
abstract: Polarized Raman microspectroscopy and atomic force microscopy were used to measure molecular orientation in individual diphenylalanine nanotubes (diameters ranging from 100 nm to 1000 nm). Analysis of the amide I Raman bands (1686 cm(-1)) indicated that the C=O side chains have a parallel alignment with the nanotube axis. The amide III Raman band (1249 cm(-1)) associated with the peptide backbone C-N vibrations showed that these bonds are preferentially aligned perpendicular to the nanotube axis. However, the Raman band corresponding to the symmetric breathing mode of the aromatic rings (1002 cm(-1)) indicated a rather random orientation. These results support the theoretical molecular structure models proposed recently.
authors.affiliation: School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK.
authors.forename: Banyat
authors.initials: B
authors.lastname: Lekprasert
authors.forename: Victoria
authors.initials: V
authors.lastname: Sedman
authors.forename: Clive J
authors.initials: CJ
authors.lastname: Roberts
authors.forename: Saul J B
authors.initials: SJ
authors.lastname: Tedler
authors.forename: Ioan
authors.initials: I
authors.lastname: Notingher
mesh_terms: D004151:Dipeptides; D018625:Microscopy, Atomic Force / Q000379:methods*; D008968:Molecular Conformation; D043942:Nanotubes / Q000737:chemistry*; D055620:Optical Phenomena; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D004151:Dipeptides; C026650:phenylalanylphenylalanine; D010649:Phenylalanine