Multiwalled carbon nanotube hybrids as MRI contrast agents

• Nikodem Kuźnik and
• Mateusz M. Tomczyk

Beilstein J. Nanotechnol. 2016, 7, 1086–1103, doi:10.3762/bjnano.7.102

• % signal intensity enhancement caused by the hybrids. For medical diagnosis, 10% signal enhancement is already sufficient to observe a visually significant contrast. PEI/PSS/oMWCNT#Yin hybrids were tested on HeLa cells and compared to hybrids functionalized additionally with FA [34]. Since HeLa cells

• exhibit high over-expression of the folate receptor, the targeting effect was remarkable and was found to reach 64% signal enhancement in reference to 45% for the non-functionalized hybrids. Lamanna and Vittorio were able to localize the marked cells by their darkened contrast and emphasized the unique

Signal enhancement in cantilever magnetometry based on a co-resonantly coupled sensor

• Julia Körner,
• Christopher F. Reiche,
• Thomas Gemming,
• Bernd Büchner,
• Gerald Gerlach and
• Thomas Mühl

Beilstein J. Nanotechnol. 2016, 7, 1033–1043, doi:10.3762/bjnano.7.96

• of our sensor design but also its potential for very sensitive magnetometry measurements while maintaining a facile oscillation detection with a conventional microcantilever setup. Keywords: cantilever magnetometry; coupled oscillator; iron-filled carbon nanotube; magnetometry; signal enhancement

• fabrication of such a sensor and then evaluate a magnetometry measurement and derive magnetic properties of an iron nanowire in order to prove the applicability of the concept and to indicate its potential for signal enhancement in magnetometry. Experimental Co-resonant concept By applying the harmonic

Hemolysin coregulated protein 1 as a molecular gluing unit for the assembly of nanoparticle hybrid structures

• Tuan Anh Pham,
• Andreas Schreiber,
• Elena V. Sturm (née Rosseeva),
• Stefan Schiller and
• Helmut Cölfen

Beilstein J. Nanotechnol. 2016, 7, 351–363, doi:10.3762/bjnano.7.32

• , TEM and cryo-TEM. Since the Hcp1_cys3 protein in the Au NP assembly is located at the interstitial sites of the Au NPs, strong Raman signal enhancement of Au NP chains formed with Hcp1_cys3 can be observed. The resulting Raman spectrum indicates a stable secondary structure of Hcp1 and the Hcp1–Au NP

• signal enhancement in the Au NP hot spot and the interstitial position of Hcp1_cys3 between two Au NPs in the Au NP network. The magnitude of the signal enhancement observed here is similar to the enhancement of 105 reported for BSA protein on gold nanocylinders [27]. The identification of the Raman

• , leading to a signal enhancement of the protein. The secondary protein structure remains intact on the NPs surface and the protein–Au binding takes place via the sulfur in the integrated cysteine group. In order to demonstrate a first application of such protein-based hybrid structures, we use our Au NP

Silica micro/nanospheres for theranostics: from bimodal MRI and fluorescent imaging probes to cancer therapy

• Shanka Walia and
• Amitabha Acharya

Beilstein J. Nanotechnol. 2015, 6, 546–558, doi:10.3762/bjnano.6.57

• the synthesized nanocomposites exhibited a signal enhancement in the T1-weighted MRI images with increasing Mn concentration. The in vitro studies performed on HeLa cells suggested cell viability of more than 80% even at a Mn concentration of 50 mg·mL−1. The combination of results obtained from flow

Localized surface plasmon resonances in nanostructures to enhance nonlinear vibrational spectroscopies: towards an astonishing molecular sensitivity

• Dan Lis and
• Francesca Cecchet

Beilstein J. Nanotechnol. 2014, 5, 2275–2292, doi:10.3762/bjnano.5.237

• silver coated beads gave an SFG signal enhancement of 730 when considering the asymmetric stretching mode, which possesses a dipole moment mainly parallel to the surface. The enhancement of the methyl symmetric stretching was one order of magnitude weaker, according to the fact that its dipole moment

• amplification was greater than 104 for a 45 nm pillar diameter and an inter-pillar distance of 150 nm (NPs surface coverage of about 5%) by comparison to the signal of CO on smooth Pt films. Note however that given the low molecular coverage, the collected SFG signal enhancement was only of a factor ca. 10

• experimental proof, the CARS signal enhancement was limited to two orders of magnitude. Opposite to SFG, a major drawback of CARS is the uneven amplification of the electronic contribution from the nanostructure body that can be orders of magnitude stronger than the molecular signal from the adsorbate [21][80

Properties of plasmonic arrays produced by pulsed-laser nanostructuring of thin Au films

• Katarzyna Grochowska,
• Katarzyna Siuzdak,
• Peter A. Atanasov,
• Carla Bittencourt,
• Anna Dikovska,
• Nikolay N. Nedyalkov and
• Gerard Śliwiński

Beilstein J. Nanotechnol. 2014, 5, 2102–2112, doi:10.3762/bjnano.5.219

• of about 107 of the Raman signal enhancement due to surface effect can be estimated. For the spectra excited at 785 nm (used to ensure non-resonant Raman excitation) the maximum Raman peak heights in Figure 6b are ≈12 × 105 at 1359 cm−1, which is close to the intensities of the fluorescence signal at

• detection based on the refractive index variations [18]. In the particular case of the self-organized NP arrays, such data are crucial for understanding the relation between the structure morphology, the near-field distribution of the optical signal due to the plasmonic resonance effect, the SERS signal

• enhancement in the mid-field, and the far-field resonant response observed via the SPR spectrum. The enhancement factor (EF) can be estimated from relation [48]: where ISERS and IR are intensities of SERS and Raman signals, and NR and NSERS are the number of molecules contributing to Raman and SERS

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

• semi-quantitative information was deduced from the band intensities. Even though nanometer size resolution information was not required, the large signal enhancement of TERS was employed here to detect a monolayer coverage of weakly scattering analytes that were not detectable with normal Raman

• the lateral resolution of TERS was not used to its full potential, but, by exploiting the signal enhancement, weak scatterers could be identified over a larger area. Thiols are used for several purposes. They can form a very thin protective layer on metal surfaces [8] or can be employed in sensorics

• , leading to a strong signal enhancement and a well-localized signal source [16][17][18][19][20]. The extent of the enhancement and, along with that, the intensity of the measured Raman signal strongly depends on the tip–surface distance [5][21][22][23]. Fluctuations in the tip–sample distance can lead to

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

• ) Periodically patterned arrays with homogenous signal enhancement must be prepared, because difficulties in the fabrication of metallic surfaces with reproducible signal enhancement hamper the routine application of SERS as a (bio)analytical tool [14]. (2) A patterned plasmonic active film is essential for

• , the signal enhancement in SERS and SEF is characterized by different dependencies on the distance between the analyte and metal surface. In order to establish rules for an analyte–metal-surface, distance dependent, signal enhancement, scanning probe microscopy (SPM)-based measurements in combination

• character of gold nanorhomb arrays. Since the signal enhancement follows the plasmonic profile, fabrication strategies were developed for the vis and NIR spectral region. Here, the geometry of the gold nanorhombs was optimized by numerical calculations to efficiently improve the emission enhancement process