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ThP04

Code: ThP04	Time Slot/Poster Number: 154	Session: Tip-Enhanced and Near-field Raman II
Nanoscale Chemical Analysis of Cell Membrane Constituents Using Tip-Enhanced Raman Spectroscopy
Lothar Opilik; Thomas Schmid; Johannes Stadler; Roman M. Balabin; Renato Zenobi
ETH Zurich, Zurich, Switzerland

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Summary
Tip-enhanced Raman spectroscopy (TERS) is an apertureless near-field technique where conventional optics are used to illuminate a metal or metalized scanning probe microscopy (SPM) tip. This tip is brought in close proximity to a sample surface leading to a significant enhancement of the Raman scattering from the molecules located in the small region under the tip apex. In our studies, TERS was successfully performed on supported lipid bilayers (SLBs) with varying complexity. The data was compared to reference spectra from individual membrane components, which were collected using confocal Raman spectroscopy as well as surface-enhanced Raman spectroscopy (SERS).

Code: ThP04	Time Slot/Poster Number: 155	Session: Tip-Enhanced and Near-field Raman II
TERS as a diagnostic tool for single virus detection
Dana Cialla¹; Tanja Deckert-Gaudig³; Michael Laue²; Robert Moeller¹; Dieter Naumann²; Volker Deckert^{1, 3}; Juergen Popp^{1, 3}
¹Friedrich-Schiller-University Jena, Jena, Germany; ²Robert Koch-Institut, Jena, Germany; ³Institute of Photonic Technology, Jena, Germany

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Summary
The identification of viruses is important in many different situations and research topics. The aim of this study is to obtain significant Raman information of single virus particles in order to establish the basis for virus discrimination. Tip-enhanced Raman scattering (TERS), combining scanning probe microscopy (SPM) with surface enhanced Raman spectroscopy (SERS) fulfils the requirements of single-particle sensitivity, fingerprint specificity and lateral resolution in the nanometer range. Within this contribution TERS spectra of a single tobacco mosaic virus are presented and demonstrate the diagnostic potential of TERS.

Code: ThP04	Time Slot/Poster Number: 156	Session: Tip-Enhanced and Near-field Raman II
TERS Measurements On Halobacterium Salinarum
Tanja Deckert-Gaudig¹; Erik Freier²; Tobias Merkendorf²; Klaus Gerwert²; Volker Deckert¹
¹IPHT - Institute of Photonic Technology, Jena, Germany; ²Ruhr-University of Bochum, Bochum, Germany

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Summary
Bacteriorhodopsin is an important component in the purple membrane of Halobacterium Salinarum. On irradiation the absorbing chromophore inside the protein transfers a proton from the cytoplasmic side of the membrane to the extracellular side. The membrane of the bacterium contains also a red membrane, enriched in beta-carotene. The surface of the bacterium is characterized with tip-enhanced Raman scattering (TERS) in order to distinguish between the different membrane constituents.

Code: ThP04	Time Slot/Poster Number: 157	Session: Tip-Enhanced and Near-field Raman II
TERS Studies Of Homogeneously Immobilized Aromatic Amino Acids
Tanja Deckert-Gaudig¹; Eva Rauls²; Volker Deckert¹
¹IPHT - Institute of Photonic Technology, Jena, Germany; ²University of Paderborn, Paderborn, Germany

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Summary
For direct sequencing of proteins with tip-enhanced Raman scattering (TERS) this method must be able to distinguish amino acids in such molecules. For that reason TERS data of selected amino acids immobilized on ultraflat nobel metal nanoplates were collected. The measurements showed that the aromatic amino acids phenylalanine, tyrosine and tryptophan are adsorbed with the aromatic system almost parallel to the metal surface. As a result the ring breath modes are hardly detectable.

Code: ThP04	Time Slot/Poster Number: 158	Session: Tip-Enhanced and Near-field Raman II
A New Approach To Sequence Proteins: TERS On Insulin Fibrils
Tanja Deckert-Gaudig¹; Evelyn Kämmer²; Volker Deckert¹
¹IPHT - Institute of Photonic Technology, Jena, Germany; ²University of Jena, Jena, Germany

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Summary
As a new approach tip-enhanced Raman scattering (TERS) is employed to unravel a protein sequence . As a model system insulin fibrils were chosen. After immobilization on a single gold nanoplate TERS spectra were recorded on the fibril on positions separated by 0.5 nm. The rise and fall of signals for distinct amino acids are evident pacing from point to point and present a first hint for the partial sequences of the protein.

Code: ThP04	Time Slot/Poster Number: 159	Session: Tip-Enhanced and Near-field Raman II
Tip-Enhanced Raman Scattering (TERS) Of Uracil Strands
Xiumei Lin^{1, 2}; Tanja Deckert-Gaudig^{1, 2}; Regina Treffer^{1, 2}; Volker Deckert^{1, 2}
¹IPHT, IPC, Jena, Germany; ²IPHT, IPC, Jena, Germany

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Summary
Tip-enhanced Raman spectroscopy (TERS), a combination of scanning probe microcopy and Raman, with the advantages of high lateral resolution and large signal enhancement, is becoming a powerful tool for bionano applications. Here we obtain TERS spectra of RNA homopolymer (uracil)-PolyU single strand immobilized on the surface of a transparent Au nanoplate. These spectra were obtained after the collection of Raman spectra of single nucleobase crystals and single PolyC strands, which further demonstrates the feasibility of direct and label-free DNA and RNA sequencing.

Code: ThP04	Time Slot/Poster Number: 160	Session: Tip-Enhanced and Near-field Raman II
Advancing Single Molecule Tip-Enhanced Raman Spectroscopy under Ultra-High Vacuum
Philip Schambach; Nicola Scott; Bruno Pettinger
Fritz-Haber Institute of the Max-Planck Society, Berlin, Germany

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Summary
We have extended and developed our UHV-tip-enhanced Raman spectroscopy (TERS) system in order to facilitate the study of adsorbates on surfaces with applications in, for example, heterogeneous catalysis. The large enhancements achievable with TERS enable correlated Raman spectroscopy and STM images of adsorbed molecules down to the single molecule level to be obtained. The addition of a sample preparation chamber to our highly sensitive set-up allows for a greater flexibility of systems to be studied. We intend to apply this in investigations of two-analyte systems and studies of non-resonant single molecules of catalytic and biological relevance.

Code: ThP04	Time Slot/Poster Number: 161	Session: Tip-Enhanced and Near-field Raman II
Tip-Enhanced Raman Scattering of Carbon Nanotubes
Ka Lung Andrew Chan; Sergei G. Kazarian
Imperial College London, London, UNITED KINGDOM

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Summary
In this work, we are presenting the difference in the performance between newly gold coated and recoated AFM tips for scanning TERS experiments. Dispersed single walled carbon nanotubes (SWCNT) are used as model sample.The tip prepared with this method was found to be unstable when laser power is greater than ~0.5 mW. A laser power of ~0.01 mW was found to be sufficient to produce a good quality scanning TERS map of SWCNT. Tip was found to be “reactivated” when it was recoated by gold sputtering, however, with less enhancement signal observed.

Code: ThP04	Time Slot/Poster Number: 162	Session: Tip-Enhanced and Near-field Raman II
DUV Tip-Enhancement in Resonance Raman Scattering using Aluminum Probes
Atsushi Taguchi¹; Norihiko Hayazawa¹; Satoshi Kawata^{1, 2}
¹Nanophotonics Laboratory, Wako, Japan; ²Department of Applied Physics, Osaka University, Suita, Osaka 565-0871, Japan

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Summary
We report the tip-enhancement of resonance Raman scattering using deep ultraviolet (DUV) excitation wavelength. The tip-enhancement was successfully demonstrated with an aluminum-coated silicon tip that acts as a plasmonic material in DUV wavelengths. Adenine nanocrystals, which were used as test samples, show electronic resonance at the 266-nm excitation used in the experiments. We also discuss several ways of preparing aluminum tips including electrochemical etching of aluminum wire as well as the thermal deposition technique.

Code: ThP04	Time Slot/Poster Number: 163	Session: Tip-Enhanced and Near-field Raman II
Atomically Flat Metal Nanoplates: Ideal Substrates For TERS Measurements
Tanja Deckert-Gaudig; Volker Deckert
IPHT - Institute of Photonic Technology, Jena, Germany

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Summary
For the detection of repetitive units in macromolecular chains such as DNA, RNA and proteins a homogeneous immobilization of the molecules is crucial. Transparent gold and silver nanoplates with a size of several micrometers turned out to be valuable for such purposes. The flatness of the metal surfaces facilitates a uniform orientation of amino acids resulting in almost identical TERS spectra.