Investigating organic multilayers by spectroscopic ellipsometry: specific and non-specific interactions of polyhistidine with NTA self-assembled monolayers

• Ilaria Solano,
• Pietro Parisse,
• Ornella Cavalleri,
• Federico Gramazio,
• Loredana Casalis and
• Maurizio Canepa

Beilstein J. Nanotechnol. 2016, 7, 544–553, doi:10.3762/bjnano.7.48

• . Optical methods based on optical reflectivity, such as surface plasmon resonance (SPR) and ellipsometry, allow for label-free, non-invasive, in situ monitoring of molecular adsorption/desorption at surfaces [34][35][36][37][38][39][40]. While SPR-based methods require supports with specific plasmonic

Antibacterial activity of silver nanoparticles obtained by pulsed laser ablation in pure water and in chloride solution

• Brunella Perito,
• Emilia Giorgetti,
• Paolo Marsili and
• Maurizio Muniz-Miranda

Beilstein J. Nanotechnol. 2016, 7, 465–473, doi:10.3762/bjnano.7.40

• (blue line). In the latter case, the plasmon resonance appears blue-shifted in both ps and ns samples. Such a shift could be attributed either to a change in the dielectric constant of the liquid environment or, more reasonably, to the different oxidation grade of the NP surfaces, where the NPs obtained

Early breast cancer screening using iron/iron oxide-based nanoplatforms with sub-femtomolar limits of detection

• Dinusha N. Udukala,
• Hongwang Wang,
• Sebastian O. Wendel,
• Aruni P. Malalasekera,
• Thilani N. Samarakoon,
• Asanka S. Yapa,
• Gayani Abayaweera,
• Matthew T. Basel,
• Pamela Maynez,
• Raquel Ortega,
• Yubisela Toledo,
• Leonie Bossmann,
• Colette Robinson,
• Katharine E. Janik,
• Olga B. Koper,
• Ping Li,
• Massoud Motamedi,
• Daniel A. Higgins,
• Gary Gadbury,
• Gaohong Zhu,
• Deryl L. Troyer and
• Stefan H. Bossmann

Beilstein J. Nanotechnol. 2016, 7, 364–373, doi:10.3762/bjnano.7.33

• sequence. A second dye (cyanine 5.5) is permanently linked to the dopamine coating (Figure 1). This design enables both, plasmon-resonance quenching (SET) [20][21] and Förster resonance energy transfer (FRET) quenching [20][22] of the tethered TCPP units. Once TCPP is released via proteolytic cleavage of

• the consensus sequence, its fluorescence will increase (for most of the nanoplatforms). The nanoplatforms for cancer detection are based on proteolytic cleavage of TCPP from the Fe/Fe3O4-core (Figure 2). Increasing the distance between the TCPP fluorophore and the nanoparticle decreases plasmon

• -resonance quenching (dipole–surface energy transfer (SET) [20][21]) from TCPP to Fe/Fe3O4 and Förster resonance energy transfer (FRET [20][22]) from TCPP to cyanine 5.5. The latter is permanently tethered to the inorganic nanoparticle. For all of the employed consensus sequences, with the exceptions of

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

• described in the Experimental section. First, we investigated the influence of ionic strength on the assembly process of Au NPs. In Figure 2, the UV–vis spectra of a Au NP solution with 2 equiv Hcp1_cys3 at different ionic strengths are shown. At low ionic strength (0–6 mmol/L) the surface plasmon resonance

• only takes place for the Hcp1_cys3-functionalized NPs, where the citrate-stabilized Au NPs remain stable as evidenced by their unchanged surface plasmon resonance at 520 nm. When the NaCl concentration exceeded 12 mM, a prompt color change to blue followed by precipitation of a blue solid was observed

• overview spectra (Figure 3A) a red shift of the transversal 520 nm plasmon resonance peak to 530 nm is observed with time and the appearance of a second longitudinal peak first around 617 nm then shifting to 650 nm at the end of the reaction. This peak position around 650 nm stays constant after 18 h. In

Mismatch detection in DNA monolayers by atomic force microscopy and electrochemical impedance spectroscopy

• Maryse D. Nkoua Ngavouka,
• Pietro Capaldo,
• Elena Ambrosetti,
• Giacinto Scoles,
• Loredana Casalis and
• Pietro Parisse

Beilstein J. Nanotechnol. 2016, 7, 220–227, doi:10.3762/bjnano.7.20

• : hybridization-based detection, detection based on thermal denaturation and protein-mediated detection [5]. For each strategy, different read-out systems and experimental designs have been reported, which include fluorescence [13], surface plasmon resonance [14][15], electrochemical [16][17], atomic force

Characterisation of thin films of graphene–surfactant composites produced through a novel semi-automated method

• Nik J. Walch,
• Alexei Nabok,
• Frank Davis and
• Séamus P. J. Higson

Beilstein J. Nanotechnol. 2016, 7, 209–219, doi:10.3762/bjnano.7.19

• -coated glass using a method of total internal reflection ellipsometry (TIRE) which revealed the enhancement of the surface plasmon resonance in thin gold films by depositing graphene layers. Keywords: characterization; ellipsometry; graphene; 1H NMR; surfactant; Introduction Since its initial discovery

• similar manner. TIRE study The surface plasmon resonance (SPR) phenomenon in graphene films deposited on thin films of gold was studied in more detail using the method of total internal reflection ellipsometry (TIRE), which was developed in the last decade [12][13][14]. TIRE experimental set-up (shown

• of deposited layers. It is quite remarkable to observe spectral features around the plasmon-resonance frequency of the gold substrate, which are not related to graphene itself [22][23] but rather appeared as a result of the interaction of π-electrons in graphene with free electrons in the gold film

Linear and nonlinear optical properties of hybrid metallic–dielectric plasmonic nanoantennas

• Mario Hentschel,
• Bernd Metzger,
• Bastian Knabe,
• Karsten Buse and
• Harald Giessen

Beilstein J. Nanotechnol. 2016, 7, 111–120, doi:10.3762/bjnano.7.13

• particles at their respective plasmon resonance. It was also shown that rough metallic films led to enhanced second-harmonic generation [25][26] as well as to enhanced Raman scattering [27][28][29][30] and that both phenomena are related to local field hot spots in the metallic films. The nonlinear optical

• exists inside the gap (in the lower row the particles have been marked for clarity). Thirdly, recent reports suggest that the nonlinearity of gold is very strong. The emission of thin layers, boosted by the presence of a plasmon resonance, yields strong signals [40][44]. We wanted to suppress the strong

Controlled graphene oxide assembly on silver nanocube monolayers for SERS detection: dependence on nanocube packing procedure

• Martina Banchelli,
• Bruno Tiribilli,
• Roberto Pini,
• Luigi Dei,
• Paolo Matteini and
• Gabriella Caminati

Beilstein J. Nanotechnol. 2016, 7, 9–21, doi:10.3762/bjnano.7.2

• molecules to large proteins by means of surface-enhanced Raman spectroscopy (SERS) [8][9]. Furthermore, these arrays offer additional sensing capabilities based on the localized surface plasmon resonance (LSPR) sensitivity to subtle changes in the refractive index of the surrounding molecular environment

• new peak at 412 nm and a broader signal centred at 640 nm; similar spectral features were already reported for metal nanoparticles on dielectric support [31][43]. These experimental and theoretical studies demonstrate that the degeneracy of the localized surface plasmon resonance (LSPR) mode is split

Chemiresistive/SERS dual sensor based on densely packed gold nanoparticles

• Sanda Boca,
• Cosmin Leordean,
• Simion Astilean and
• Cosmin Farcau

Beilstein J. Nanotechnol. 2015, 6, 2498–2503, doi:10.3762/bjnano.6.259

• plasmon resonance, surface-enhanced fluorescence or surface-enhanced Raman spectroscopy (SERS) [2][3]. Among these analytical techniques, SERS is particularly interesting because it can specifically identify the analyte by the unique vibrational signature of chemical groups. Another class of promising

Surface-enhanced Raman scattering by colloidal CdSe nanocrystal submonolayers fabricated by the Langmuir–Blodgett technique

• Alexander G. Milekhin,
• Larisa L. Sveshnikova,
• Tatyana A. Duda,
• Ekaterina E. Rodyakina,
• Volodymyr M. Dzhagan,
• Ovidiu D. Gordan,
• Sergey L. Veber,
• Cameliu Himcinschi,
• Alexander V. Latyshev and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2015, 6, 2388–2395, doi:10.3762/bjnano.6.245

• deposited NCs was less than one monolayer, as determined by transmission and scanning electron microscopy. SERS by optical phonons in CdSe nanocrystals showed a significant enhancement that depends resonantly on the Au nanocluster and dimer size, and thus on the localized surface plasmon resonance (LSPR

• ; localized surface plasmon resonance; metal nanoclusters; phonons; surface-enhanced Raman spectroscopy; Introduction Since its observation in 1974 [1], surface-enhanced Raman scattering (SERS) has become a powerful technique for detecting and studying ultra-low quantities of organic and biological

• rough metal surfaces. The locally enhanced electromagnetic field induced by the localized surface plasmon resonance (LSPR) in the vicinity of metal surface is responsible for the Raman scattering intensity enhancement, which is proportional to the fourth power of the enhancement of the local field [3][4

Green and energy-efficient methods for the production of metallic nanoparticles

• Mitra Naghdi,
• Mehrdad Taheran,
• Satinder K. Brar,
• M. Verma,
• R. Y. Surampalli and
• J. R. Valero

Beilstein J. Nanotechnol. 2015, 6, 2354–2376, doi:10.3762/bjnano.6.243

• range of 40–200 nm [86]. Also, Wei et al. used CTS in aqueous solution of AgNO3 and HAuCl4 to act as reducing agent and scaffold for the formation of Au and Ag NPs. They used surface plasmon resonance (SPR) analysis to confirm the formation of NPs [29]. In related reports, they used TEM analysis and

Self-organization of gold nanoparticles on silanated surfaces

• Htet H. Kyaw,
• Salim H. Al-Harthi,
• Azzouz Sellai and
• Joydeep Dutta

Beilstein J. Nanotechnol. 2015, 6, 2345–2353, doi:10.3762/bjnano.6.242

• are fundamentally important and also can be applied for designing and modelling of surface plasmon resonance based sensor applications. Keywords: 3-aminopropyletriethoxysilane; electrostatic interaction; functionalization; gold nanoparticles; self-assembled monolayer; self-organization; Introduction

• structures [8]. AuNPs have been studied intensively for a wide range of applications such as catalysis [9], biosensing [10], colorimetric sensing [11], optical sensing (surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS)) [12][13], photonics [13][14], photovoltaic devices [15] and

• photothermal therapy [16]. AuNPs exhibit well-defined optical properties such as surface plasmon resonance, which depends on the size and shape of nanoparticles, interparticle distance and the effective refractive index of the surrounding medium [17]. Different techniques have been used to assemble AuNPs on

Orthogonal chemical functionalization of patterned gold on silica surfaces

• Francisco Palazon,
• Didier Léonard,
• Thierry Le Mogne,
• Francesca Zuttion,
• Céline Chevalier,
• Magali Phaner-Goutorbe,
• Éliane Souteyrand,
• Yann Chevolot and
• Jean-Pierre Cloarec

Beilstein J. Nanotechnol. 2015, 6, 2272–2277, doi:10.3762/bjnano.6.233

• with the development of localized surface plasmon resonance (LSPR) biosensors, this topic has become a major focus [2][3][4][5][6][7][8]. Indeed, LSPR transduction is expected to yield enhanced signal as compared to classical SPR transduction. However, the enhancement of the LSPR limit of detection is

Au nanoparticle-based sensor for apomorphine detection in plasma

• Chiara Zanchi,
• Andrea Lucotti,
• Matteo Tommasini,
• Sebastiano Trusso,
• Ugo de Grazia,
• Emilio Ciusani and
• Paolo M. Ossi

Beilstein J. Nanotechnol. 2015, 6, 2224–2232, doi:10.3762/bjnano.6.228

• frequency and width of the plasmon resonance, that can be tailored exploring wide intervals [26]. This makes them suitable for use as substrates for SERS, and in particular, to detect exiguous amounts of analyte with low-intensity Raman signatures or that are hindered by competitive fluorescence. A thorough

•  1A show typical average sizes of such inter-island channels. SERS hinges on the strong interaction between noble metal NPs and visible light through the resonant collective excitation of NP conduction electrons. The resulting surface plasmon resonance peak [28] displays a maximum at about 780 nm

Conformational switching of ethano-bridged Cu,H₂-bis-porphyrin induced by aromatic amines

• Simona Bettini,
• Emanuela Maglie,
• Rosanna Pagano,
• Victor Borovkov,
• Yoshihisa Inoue,
• Ludovico Valli and
• Gabriele Giancane

Beilstein J. Nanotechnol. 2015, 6, 2154–2160, doi:10.3762/bjnano.6.221

• bis-porphyrin derivative. The Langmuir–Schaefer technique has been used to transfer the floating bis-porphyrin film (when using pure water as a subphase) to a surface plasmon resonance (SPR) substrate and the resulting device was able to detect the presence of aniline at concentrations as low as 1 nM

• were deposited on the SPR slide, and the shift of the SPR angle induced by the injection of amine aqueous solutions at different concentrations was monitored. The effect of aniline on the plasmon resonance of the Cu,H2-Por2 film could be detected when only 1 nM of analyte was fluxed over the active

• -logarithmic trend was proposed [22][23][24]. The recovery of the SPR device was investigated. The initial plasmon resonance angle was obtained when the Cu,H2-Por2 LS film, previously exposed to aniline, was treated for 15 min at 50 °C and then washed with a flow of ultrapure water for 5 min. The response of

Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials

• Xiaoxing Ke,
• Carla Bittencourt and
• Gustaaf Van Tendeloo

Beilstein J. Nanotechnol. 2015, 6, 1541–1557, doi:10.3762/bjnano.6.158

• defect, as imaged by STEM, can act as an atomic antenna in the frequency range of petahertz, and thus enhance the surface plasmon resonance locally. However, more recently, Nelson et al., after extracting the dielectric function from STEM–EELS spectra and comparing it with the calculated results [103

Formation of substrate-based gold nanocage chains through dealloying with nitric acid

• Ziren Yan,
• Ying Wu and
• Junwei Di

Beilstein J. Nanotechnol. 2015, 6, 1362–1368, doi:10.3762/bjnano.6.140

• to their solid counterparts because of the high surface area, low density, and near-infrared localized surface plasmon resonance (LSPR). All these make Au NC an attractive material for various applications in optical [4][5] and electrochemical sensing [6], immunoassay [7], drug release [8], surface

• solution on a copper grid. X-ray diffraction (XRD) analysis was performed by X’Pert-Pro MPD (Panalytical, Holland). The localized surface plasmon resonance (LSPR) spectra of nanoparticles were measured with a Shimadzu UV–vis–NIR 3600 Spectrophotometer against a bare ITO slide as the reference. SEM images

Synthesis, characterization and in vitro effects of 7 nm alloyed silver–gold nanoparticles

• Simon Ristig,
• Svitlana Chernousova,
• Wolfgang Meyer-Zaika and
• Matthias Epple

Beilstein J. Nanotechnol. 2015, 6, 1212–1220, doi:10.3762/bjnano.6.124

• resonance peak shows one maximum due to the distribution of the metals throughout the whole particle. Core–shell nanoparticles or individual silver or gold nanoparticles show two distinct plasmon resonance peaks [21][36][37]. As it is depicted in Figure 3, the absorption spectra show only one narrow peak

• plasmon resonance spectra against the molar fraction of Au or Ag. For a given particle size and surface functionalization, a linear relationship would indicate a macroscopically homogeneous distribution of the metals in the nanoparticles [21]. In Figure 4, the absorption maxima of the ≈10 nm nanoparticles

• values were close to the theoretical compositions (Table 2). To confirm the alloying of the two metals, UV–vis spectra were recorded for all samples. From the spectra it is possible to gain information about the inner structure of the nanoparticles. In case of alloyed Ag/Au nanoparticles, the plasmon

Improved optical limiting performance of laser-ablation-generated metal nanoparticles due to silica-microsphere-induced local field enhancement

• Zheren Du,
• Lianwei Chen,
• Tsung-Sheng Kao,
• Mengxue Wu and
• Minghui Hong

Beilstein J. Nanotechnol. 2015, 6, 1199–1204, doi:10.3762/bjnano.6.122

• nanoparticles exhibit localized surface plasmon resonance (LSPR), which is another possible way for local field enhancement to influence the light absorption and scattering [25]. Conclusion In this paper, we have studied that LAL is a promising technique to generate nanoparticles for various target materials

Superluminescence from an optically pumped molecular tunneling junction by injection of plasmon induced hot electrons

• Kai Braun,
• Xiao Wang,
• Andreas M. Kern,
• Hilmar Adler,
• Heiko Peisert,
• Thomas Chassé,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2015, 6, 1100–1106, doi:10.3762/bjnano.6.111

• power, PIL < 25%, a high-gain regime for 25% < PIL < 75% and almost saturates for PIL > 75%. The intensity in the low-gain regime consists mainly of the luminescence from the plasmon resonance of the Au/Au-junction and the spectrum has a full width at half maximum of about 90 nm with very weak

• scattered to the far field. While the gap modes plasmon resonance is very broad, exhibiting a quality factor of only Q ≈ 15, the resonantly stored energy in the optical near field in the gap is extremely well localized, in a volume having an upper limit of approximately 4 × 4 × 1 nm3 (see Figure S8

Patterning technique for gold nanoparticles on substrates using a focused electron beam

• Takahiro Noriki,
• Shogo Abe,
• Kotaro Kajikawa and
• Masayuki Shimojo

Beilstein J. Nanotechnol. 2015, 6, 1010–1015, doi:10.3762/bjnano.6.104

• plasmon resonance (LSPR) are attracting attention for future optical transmission, sensor, and data processing devices. The development of these LSPR-based structures would lead to a reduction in the size of optical circuits and devices [1][2]. Light energy can be propagated through nanometer-sized wires

Protein corona – from molecular adsorption to physiological complexity

• Lennart Treuel,
• Dominic Docter,
• Michael Maskos and
• Roland H. Stauber

Beilstein J. Nanotechnol. 2015, 6, 857–873, doi:10.3762/bjnano.6.88

• adsorption such as isothermal titration calorimetry (ITC) [82][83], and surface plasmon resonance (SPR) [22][84]. Moreover, techniques based on the size of proteins and protein–NP complexes have been utilized such as size-exclusion chromatography (SEC) [85][86][87][88][89][90] or one- and two-dimensional

Combination of surface- and interference-enhanced Raman scattering by CuS nanocrystals on nanopatterned Au structures

• Alexander G. Milekhin,
• Nikolay A. Yeryukov,
• Larisa L. Sveshnikova,
• Tatyana A. Duda,
• Ekaterina E. Rodyakina,
• Victor A. Gridchin,
• Evgeniya S. Sheremet and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2015, 6, 749–754, doi:10.3762/bjnano.6.77

• surface plasmon resonance energy enabling resonance SERS in absorbates deposited on the arrays [13][14][15][16][17]. Moreover, CuS NCs are resistant against intense laser excitation even under resonant conditions. This is important for micro-Raman experiments with the NCs on nanostructured Au arrays under

Electromagnetic enhancement of ordered silver nanorod arrays evaluated by discrete dipole approximation

• Guoke Wei,
• Jinliang Wang and
• Yu Chen

Beilstein J. Nanotechnol. 2015, 6, 686–696, doi:10.3762/bjnano.6.69

• under the s-polarized and the p-polarized excitations are also depicted in Figure 2, in which the propagation direction of the light is perpendicular to the long axis of the nanorod. A major plasmon resonance peak centred at 360 nm is found under the excitation of s-polarization, along with a broad

• shows a similar trend against AR as EFavg does. Effect of the excitation wavelength Since the SERS effect is a near-field phenomenon and related to the localized surface plasmon resonance (LSPR) of the nanostructures, it is expected to exhibit a behavior that depends on the excitation wavelength. Here

• the vertical AgNR arrays. It has been revealed that different modes of surface plasmon resonance can only be excited by certain angles of incidence, leading to different near-field enhancements [23][33]. Effect of incident polarization Figure 9a shows the polarization dependence of EFavg from S42 AgNR

Influence of gold, silver and gold–silver alloy nanoparticles on germ cell function and embryo development

• Ulrike Taylor,
• Daniela Tiedemann,
• Christoph Rehbock,
• Wilfried A. Kues,
• Stephan Barcikowski and
• Detlef Rath

Beilstein J. Nanotechnol. 2015, 6, 651–664, doi:10.3762/bjnano.6.66

• nanotoxicology on reproductive cells provides an ideal tool. Schematic representation of experiments conducted within the collaboration project REPROTOX. (A) Exemplary AuAg colloids with different molar fractions. (B) Correlation of gold molar fraction with the maximum surface plasmon resonance extinction peak