title: Reflection-mode TERS on Insulin Amyloid Fibrils with Top-Visual AFM Probes.
abstract: Tip-enhanced Raman spectroscopy provides chemical information while raster scanning samples with topographical detail. The coupling of atomic force microscopy and Raman spectroscopy in top illumination optical setup is a powerful configuration to resolve nanometer structures while collecting reflection mode backscattered signal. Here, we theoretically calculate the field enhancement generated by TER spectroscopy with top illumination geometry and we apply the technique to the characterization of insulin amyloid fibrils. We experimentally confirm that this technique is able to enhance the Raman signal of the polypeptide chain by a factor of 105, thus revealing details down to few molecules resolution.
authors.affiliation: Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
authors.forename: Manola
authors.initials: M
authors.lastname: Moretti
authors.forename: Remo
authors.initials: R
authors.lastname: Proietti Zaccaria
authors.forename: Emiliano
authors.initials: E
authors.lastname: Descrovi
authors.forename: Gobind
authors.initials: G
authors.lastname: Das
authors.forename: Marco
authors.initials: M
authors.lastname: Leoncini
authors.forename: Carlo
authors.initials: C
authors.lastname: Liberale
authors.forename: Francesco
authors.initials: F
authors.lastname: De Angelis
authors.forename: Enzo
authors.initials: E
authors.lastname: Di Fabrizio
keywords: Amyloid fibrils; Field enhancement; Raman spectroscopy; TERS; Top-illumination setup