Distinction of nucleobases – a tip-enhanced Raman approach

• Regina Treffer,
• Xiumei Lin,
• Elena Bailo,
• Tanja Deckert-Gaudig and
• Volker Deckert

Beilstein J. Nanotechnol. 2011, 2, 628–637, doi:10.3762/bjnano.2.66

• a sequencing procedure with TERS is the fact that the four nucleobases reveal remarkably different Raman scattering cross sections. It was shown that in SERS experiments on an equimolar mixture of the bases, the intensities of the ring breathing modes of the distinct bases are as follows: Poly

• -adenine > poly-cytosine >> poly-guanine > poly-thymine [24]. Furthermore, in a comparison of the SERS spectra of two DNA molecules with different adenine contents (15.5% and 44.3%), the adenine signals dominated [25]. Hence it was predicted that signals from adenine only are likely to be detected when

• assignment the spectral features were compared with those of SERS and Raman spectra of adenine derivates (deoxyadenosine (dA) [27], deoxyadenosine monophosphate (AMP) [28] and single stranded adenine homopolymer (poly(dA)) [29]). A comparison of TERS and SERS spectra of adenine (or any other molecule) must

Tip-enhanced Raman spectroscopic imaging of patterned thiol monolayers

• Johannes Stadler,
• Thomas Schmid,
• Lothar Opilik,
• Phillip Kuhn,
• Petra S. Dittrich and
• Renato Zenobi

Beilstein J. Nanotechnol. 2011, 2, 509–515, doi:10.3762/bjnano.2.55

• molecular monolayers, an enhanced Raman technique is necessary to determine the chemical identity of the molecules. In surface-enhanced Raman spectroscopy (SERS) experiments (with a rough Ag film as a substrate, produced by vapor coating with randomly located enhancement hot-spots), the necessary

• enhancement can in principle be reached. An attempt was made to visualize the distribution of molecules using SERS, but this did not yield satisfactory results. However, the large signal-to-noise ratio in every pixel of a TERS image allows one to obtain enough information to distinguish a full monolayer from

• decomposition products (carbonaceous decomposition products usually scatter strongly) leads to the conclusion that the SAM was not destroyed by the high laser power, but that the intensity of Raman signals from the intact monolayer was too weak to be detected. In experiments on Ag SERS substrates (nominal

Towards multiple readout application of plasmonic arrays

• Dana Cialla,
• Karina Weber,
• René Böhme,
• Uwe Hübner,
• Henrik Schneidewind,
• Matthias Zeisberger,
• Roland Mattheis,
• Robert Möller and
• Jürgen Popp

Beilstein J. Nanotechnol. 2011, 2, 501–508, doi:10.3762/bjnano.2.54

• , Albert-Einstein-Straße 9, 07745 Jena, Germany 10.3762/bjnano.2.54 Abstract In order to combine the advantages of fluorescence and surface-enhanced Raman spectroscopy (SERS) on the same chip platform, a nanostructured gold surface with a unique design, allowing both the sensitive detection of

• fluorescence light together with the specific Raman fingerprint of the fluorescent molecules, was established. This task requires the fabrication of plasmonic arrays that permit the binding of molecules of interest at different distances from the metallic surface. The most efficient SERS enhancement is

• article, the simultaneous application of SERS and fluorescence, through the use of various gold nanostructured arrays, is demonstrated by the realization of a DNA detection scheme. The results shown open the way to more flexible use of plasmonic arrays in bioanalytics. Keywords: fluorescence; multiple

Plasmonic nanostructures fabricated using nanosphere-lithography, soft-lithography and plasma etching

• Manuel R. Gonçalves,
• Taron Makaryan,
• Fabian Enderle,
• Stefan Wiedemann,
• Alfred Plettl,
• Othmar Marti and
• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 448–458, doi:10.3762/bjnano.2.49

• as surface enhanced Raman spectroscopy (SERS) [28][29][30][31] and, more recently, in studies of fluorescence lifetime [32][33] and the enhancement of the Purcell rate [34] (achieved mainly by confinement of light in small mode volumes rather than by very large Q-values of the resonances). The strong

Manipulation of gold colloidal nanoparticles with atomic force microscopy in dynamic mode: influence of particle–substrate chemistry and morphology, and of operating conditions

• Samer Darwich,
• Karine Mougin,
• Akshata Rao,
• Enrico Gnecco,
• Shrisudersan Jayaraman and
• Hamidou Haidara

Beilstein J. Nanotechnol. 2011, 2, 85–98, doi:10.3762/bjnano.2.10

• detection (colorimetric and surface enhanced Raman spectroscopy (SERS)). For different reasons gold particles are particularly attractive in this field. For instance, they are ideal electrodes for molecular electronics [22]. Gold clusters below 5 nm in size deposited onto thin metal oxides also exhibit