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Sub-Tip-Radius Near-Field Interactions in Nano-FTIR Vibrational Spectroscopy on Single Proteins.
Nishida, Jun; Otomo, Akihiro; Koitaya, Takanori; Shiotari, Akitoshi; Minato, Taketoshi; Iino, Ryota; Kumagai, Takashi.
Afiliação
  • Nishida J; Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan.
  • Otomo A; The Graduate Institute for Advanced Studies, SOKENDAI, Hayama, Kanagawa 240-0193, Japan.
  • Koitaya T; Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan.
  • Shiotari A; The Graduate Institute for Advanced Studies, SOKENDAI, Hayama, Kanagawa 240-0193, Japan.
  • Minato T; Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan.
  • Iino R; Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
  • Kumagai T; Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan.
Nano Lett ; 24(3): 836-843, 2024 Jan 24.
Article em En | MEDLINE | ID: mdl-38193723
ABSTRACT
Tip-enhanced vibrational spectroscopy has advanced to routinely attain nanoscale spatial resolution, with tip-enhanced Raman spectroscopy even achieving atomic-scale and submolecular sensitivity. Tip-enhanced infrared spectroscopy techniques, such as nano-FTIR and AFM-IR spectroscopy, have also enabled the nanoscale chemical analysis of molecular monolayers, inorganic nanoparticles, and protein complexes. However, fundamental limits of infrared nanospectroscopy in terms of spatial resolution and sensitivity have remained elusive, calling for a quantitative understanding of the near-field interactions in infrared nanocavities. Here, we demonstrate the application of nano-FTIR spectroscopy to probe the amide-I vibration of a single protein consisting of ∼500 amino acid residues. Detection with higher tip tapping demodulation harmonics up to the seventh order leads to pronounced enhancement in the peak amplitude of the vibrational resonance, originating from sub-tip-radius geometrical effects beyond dipole approximations. This quantitative characterization of single-nanometer near-field interactions opens the path toward employing infrared vibrational spectroscopy at the subnanoscale and single-molecule levels.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Rádio (Anatomia) / Vibração Idioma: En Revista: Nano Lett Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Japão

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Rádio (Anatomia) / Vibração Idioma: En Revista: Nano Lett Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Japão