Label-free investigation of biomolecules on the nanometer scale using Tip-enhanced Raman Spectroscopy

摘要

In this contribution we present results of tip-enhanced Raman spectroscopy (TERS) measurements on a single crystal of cystine. The observed spectral features lead to the conclusion that the S-S bond was cleaved due to interactions with the silver tip. The spectra differ strongly depending on the site of the molecule interacting with the silver tip. Additionally, first TERS spectra bovine serum albumin (BSA) indicate, that the disulfide bridges of cystine in the protein remain unchanged. This fact can be used for a structural discussion of the secondary structure of the protein. A thorough band assignment was feasible based on an extensive collection of previously obtained TERS spectra of selected amino acids.