The role of Ag⁺, Ca²⁺, Pb²⁺ and Al³⁺ adions in the SERS turn-on effect of anionic analytes

• Stefania D. Iancu,
• Andrei Stefancu,
• Vlad Moisoiu,
• Loredana F. Leopold and
• Nicolae Leopold

Beilstein J. Nanotechnol. 2019, 10, 2338–2345, doi:10.3762/bjnano.10.224

• technique with detection limits below nanomolar concentrations and is able to resolve single molecules of cationic dyes such as rhodamine 6G or crystal violet. The SERS detection of such cationic analytes has been achieved by using chloride-activated colloids, with chloride assuming the role of an

• AgNPs were immobilized on a glass surface [12]. Recently, we brought further evidence for the role of the Cl− adion in the SERS detection of cationic molecules, showing that Cl− (but also Br− or I−) adions promote the chemisorption of cationic dyes to the silver surface leading to the turn-on of the

• were able to detect the SERS signal of the cationic dyes only after facilitating the chemisorption of Cl− ions by Ag+, Ca2+ or Mg2+ adions [13][14]. We explained this surface process by an adion-specific adsorption model and the SERS enhancement in the context of the electronic mechanism of SERS, which

Review of advanced sensor devices employing nanoarchitectonics concepts

• Katsuhiko Ariga,
• Tatsuyuki Makita,
• Masato Ito,
• Taizo Mori,
• Shun Watanabe and
• Jun Takeya

Beilstein J. Nanotechnol. 2019, 10, 2014–2030, doi:10.3762/bjnano.10.198

• interaction and faint differences. Kim and co-workers fabricated sensor arrays that were engineered with fluorescence dyes and cucurbit[n]urils (n = 6, 7 and 8) as host systems [91]. The obtained sensors were used for sensing biogenic amines with the aid of principal component analysis. This

Optimization and performance of nitrogen-doped carbon dots as a color conversion layer for white-LED applications

• Tugrul Guner,
• Hurriyet Yuce,
• Didem Tascioglu,
• Eren Simsek,
• Umut Savaci,
• Aziz Genc,
• Servet Turan and
• Mustafa M. Demir

Beilstein J. Nanotechnol. 2019, 10, 2004–2013, doi:10.3762/bjnano.10.197

• perovskites [39][40][41], organic dyes [42][43], quantum dots [44] and CDots [15][45]. Among these, CDots are a promising alternative since they are cost effective and optically feasible, making them commercially viable. Employing CDots as color conversion layers in a WLED configuration is a relatively new

Porous silver-coated pNIPAM-co-AAc hydrogel nanocapsules

• William W. Bryan,
• Riddhiman Medhi,
• Maria D. Marquez,
• Supparesk Rittikulsittichai,
• Michael Tran and
• T. Randall Lee

Beilstein J. Nanotechnol. 2019, 10, 1973–1982, doi:10.3762/bjnano.10.194

• various core materials [21][22][23][24]. Recent studies involving spherical capsules have introduced a variety of materials into the core such as DNA, antibiotics, fluorescent dyes, and metal nanoparticles [25][26][27][28][29][30]. These types of particles show great promise for applications such as drug

High-tolerance crystalline hydrogels formed from self-assembling cyclic dipeptide

• Yongcai You,
• Ruirui Xing,
• Qianli Zou,
• Feng Shi and
• Xuehai Yan

Beilstein J. Nanotechnol. 2019, 10, 1894–1901, doi:10.3762/bjnano.10.184

• ) (Figure 2A). Thioflavin T (ThT) and nile red (NR), two specific dyes for hydrophobic domains and beta-sheet secondary structures, respectively, were used to obtain insights into the detailed interior structure of the hydrogel [49]. CLSM results confirmed that the C-WY hydrogel contains both hydrophobic

Toxicity and safety study of silver and gold nanoparticles functionalized with cysteine and glutathione

• Barbara Pem,
• Igor M. Pongrac,
• Lea Ulm,
• Ivan Pavičić,
• Valerije Vrček,
• Darija Domazet Jurašin,
• Marija Ljubojević,
• Adela Krivohlavek and
• Ivana Vinković Vrček

Beilstein J. Nanotechnol. 2019, 10, 1802–1817, doi:10.3762/bjnano.10.175

• apoptotic/dead cells were determined by flow cytometry analysis after staining with CAM and EthD dyes. The doses that caused low or no significant reduction in cell viability (Figure 4a) showed apoptotic processes in a dose-response manner for all tested species (Figure 4b). In accordance with the MTT data

• , Hamburg, Germany). After treatment with AgNPs or AuNPs (at 5 mg Ag/Au L−1), the cells were washed with PBS, fixed with ice-cold methanol (−20 °C), and stained with F-actin-phalloidin and Hoechst 33258 nucleic acid dyes. The slides were then mounted in Fluoroshield Antifade Mounting Medium and their images

• evaluation of SSC signals that may be triggered by NPs. The highest concentration of each NP solution was run first to set the range for the maximum SSC signal. Gate settings for each experiment were performed using several different positive and negative controls, including NPs with and without dyes

Layered double hydroxide/sepiolite hybrid nanoarchitectures for the controlled release of herbicides

• Ediana Paula Rebitski,
• Margarita Darder and
• Pilar Aranda

Beilstein J. Nanotechnol. 2019, 10, 1679–1690, doi:10.3762/bjnano.10.163

• removal of pollutants from water, for instance dyes [31] and, As(III) and As(V) species [34]. Moreover, they could be used as precursors for supported metal-oxide nanoparticles that could be of interest in catalysis [31]. MgAl-LDH/sepiolite nanoarchitectures have been also satisfactorily tested as

Materials nanoarchitectonics at two-dimensional liquid interfaces

• Katsuhiko Ariga,
• Michio Matsumoto,
• Taizo Mori and
• Lok Kumar Shrestha

Beilstein J. Nanotechnol. 2019, 10, 1559–1587, doi:10.3762/bjnano.10.153

• -exchangers, and indicative dyes were incorporated in an optode system detecting caesium ions in tap water and seawater [80]. Photo-controllable molecular devices were successfully fabricated using two-dimensional self-assembled monolayer technology as recently reviewed by Suda [81]. Hierarchic functional

BiOCl/TiO₂/diatomite composites with enhanced visible-light photocatalytic activity for the degradation of rhodamine B

• Minlin Ao,
• Kun Liu,
• Xuekun Tang,
• Zishun Li,
• Qian Peng and
• Jing Huang

Beilstein J. Nanotechnol. 2019, 10, 1412–1422, doi:10.3762/bjnano.10.139

• photocatalyst prepared by dispersing TiO2 and BiOCl on the surface of diatomite for the first time. Rhodamine B (RhB) is one of the most commonly used dyes and is a highly toxic compound with potential carcinogenicity. It is often used in textile, painting, chemical and other industries. RhB released from these

• indicates that BiOCl and TiO2 are mainly dispersed on the surface of diatomite, but not in the pores. The larger pore volume will be beneficial to the enrichment and degradation of dyes, thus showing a higher catalytic performance [33]. The surface chemical state of BTD was characterized by XPS. The survey

Green fabrication of lanthanide-doped hydroxide-based phosphors: Y(OH)₃:Eu³⁺ nanoparticles for white light generation

• Tugrul Guner,
• Anilcan Kus,
• Mehmet Ozcan,
• Aziz Genc,
• Hasan Sahin and
• Mustafa M. Demir

Beilstein J. Nanotechnol. 2019, 10, 1200–1210, doi:10.3762/bjnano.10.119

• as quantum dots [22], perovskites [23], organic dyes [24], etc. In the case of phosphors, combining a red phosphor with YAG:Ce3+ over a blue LED is the simplest way of increasing the CRI while reducing the CCT. Phosphors mostly consist of thermally and chemically stable inorganic hosts such as YAG

A highly efficient porous rod-like Ce-doped ZnO photocatalyst for the degradation of dye contaminants in water

• Binjing Hu,
• Qiang Sun,
• Chengyi Zuo,
• Yunxin Pei,
• Siwei Yang,
• Hui Zheng and
• Fangming Liu

Beilstein J. Nanotechnol. 2019, 10, 1157–1165, doi:10.3762/bjnano.10.115

• ; Introduction Organic dyes used in the textile and dye industries account for a large proportion of pollutants in wastewater. Most of the organic dyes used are difficult to degrade, resulting in irreversible damage to the environment [1]. Although many efficient approaches have been applied to manage this

• ]. Recently, photocatalytic degradation of organic dyes using semiconductors has attracted much attention [6]. This refers to the process in which organic compounds are gradually oxidized into inorganic compounds or even H2O and CO2 under the synergistic effects of light and photocatalysis. ZnO is one of the

• levels serve as electron traps for photogenerated electrons. In this way, the recombination of photoinduced holes and electrons is suppressed, which accelerates the transfer of electrons to dissolve oxygen molecules and to produce more superoxide radicals to degrade probe dyes [9][22]. As a result, CZO-4

Photoactive nanoarchitectures based on clays incorporating TiO₂ and ZnO nanoparticles

• Eduardo Ruiz-Hitzky,
• Pilar Aranda,
• Marwa Akkari,
• Nithima Khaorapapong and
• Makoto Ogawa

Beilstein J. Nanotechnol. 2019, 10, 1140–1156, doi:10.3762/bjnano.10.114

• photodegradation of diverse organic compounds, including the photodecolorization of dyes such as methylene blue (MB), methyl green (MG), acid red G, acid yellow 11, acid orange 11, and Congo red, in water, as well as other photo-applications, for instance, water splitting under UV or visible/solar light

• harmful organic compounds, such as pesticides, phenols, dyes, and pharmaceuticals drugs to water, CO2, and non-toxic inorganic residues under solar light or UV irradiation. Advantages such as low cost and chemical stability are essential requirements of this type of photocatalysts [25][26]. In addition

• surface area values are of the order of 50–100 m2/g whereas the ZnO NPs alone exhibit values below 15 m2/g. The mesoporosity (ca. 0.25 cm3/g total porosity) together the photoactivity of the ZnO NPs make these materials suitable photocatalysts for the removal of organic dyes from water [118]. ZnO–clay

Correlation of surface-enhanced Raman scattering (SERS) with the surface density of gold nanoparticles: evaluation of the critical number of SERS tags for a detectable signal

• Vincenzo Amendola

Beilstein J. Nanotechnol. 2019, 10, 1016–1023, doi:10.3762/bjnano.10.102

• dyes without AuNTs under the same experimental conditions. Moreover, it is well known from literature that the utilization of Au NPs of the same size is associated with higher SERS enhancement factors [18], therefore suggesting that the performance of the AuNTs can be further improved by employing size

• -selected nanospheres. Conclusion In this study, the performance of SERS labels based on Au NPs and organic dyes resonant at 633 nm was investigated by a combination of Raman and TEM analysis. The AuNTs were designed in order to support multiple electromagnetic hot spots for any polarization direction of

Comparing a porphyrin- and a coumarin-based dye adsorbed on NiO(001)

• Sara Freund,
• Antoine Hinaut,
• Nathalie Marinakis,
• Edwin C. Constable,
• Ernst Meyer,
• Catherine E. Housecroft and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2019, 10, 874–881, doi:10.3762/bjnano.10.88

• technologies such as dye-sensitized solar cells. A key optimization parameter for such devices is the choice of the compounds in order to control the direction and the intensity of charge transfer across the interface. Here, the deposition of two different molecular dyes, porphyrin and coumarin, as single

• semiconductor after photon absorption [17][19][20], resulting in an electron transfer from the surface of the semiconductor towards the dyes (see Figure 1a). In other terms, the direction of charge transfer relies on the electron affinity of the dyes and on their HOMO and LUMO levels compared to the CB and VB

• of the semiconductor. Typically, dyes are specifically designed to be compatible with one or the other type of device. Consequently, the careful choice of the dye is crucial for the optimal function of n- or p-type DSSCs. Because of its electron-donor character, copper(II) meso-tetrakis(4

Polydopamine-coated Au nanorods for targeted fluorescent cell imaging and photothermal therapy

• Boris N. Khlebtsov,
• Andrey M. Burov,
• Timofey E. Pylaev and
• Nikolai G. Khlebtsov

Beilstein J. Nanotechnol. 2019, 10, 794–803, doi:10.3762/bjnano.10.79

• . Meanwhile different imaging and therapeutic agents can be loaded into the shell of multifunctional nanocomposites. Various AuNR-based nanocomposites loaded with anticancer drugs [17][18][19], photodynamic dyes [20][21], MRI contrast agents [22] and many others ligands [23][24] have already been reported for

• capacity for various cargo molecules such as drugs or photodynamic dyes. Third, the coating should have functional groups and be ready for click conjugation with target or “shadowing” molecules, e.g., antibodies, peptides, folates and PEG. Finally, the AuNR coating procedure should be robust and provide a

• provides additional potential advantages for in vivo experiments as compared to other inorganic coatings such as silica shells. It is well known [46] that the adsorption of fluorescent dyes on Au nanoparticles can induce quenching of their emission. However, in the AuNRs-PDA-R123-folate, the PDA layer

Towards rare-earth-free white light-emitting diode devices based on the combination of dicyanomethylene and pyranine as organic dyes supported on zinc single-layered hydroxide

• Jeff L. Nyalosaso,
• Rachod Boonsin,
• Pierre Vialat,
• Damien Boyer,
• Geneviève Chadeyron,
• Rachid Mahiou and
• Fabrice Leroux

Beilstein J. Nanotechnol. 2019, 10, 760–770, doi:10.3762/bjnano.10.75

• luminescent organic dyes in a single-layered hydroxide (SLH)-type inorganic matrix has been developed. Two fluorescent organic dyes emitting visible light upon blue LED excitation were investigated in this study: dicyanomethylene (DCM) and pyranine (HPTS). These dyes exhibit broad emission bands that cover a

• large part of the visible spectrum. The concept developed in our work consisted in keeping SLH in its wet form to ensure a good dispersion of the fluorescent dyes prior to immobilizing the hybrid materials in a silicone polymer to achieve luminescent composite films. We demonstrate that these coatings

• issue. In this context, it seems crucial to identify new cheap and REE-free phosphors capable of delivering cost-effective light energy conversion. Luminescent organic dyes are a relevant alternative to REEs. Indeed, they are known to exhibit high luminous efficiency at low cost and may be associated

Ceria/polymer nanocontainers for high-performance encapsulation of fluorophores

• Kartheek Katta,
• Dmitry Busko,
• Yuri Avlasevich,
• Katharina Landfester,
• Stanislav Baluschev and
• Rafael Muñoz-Espí

Beilstein J. Nanotechnol. 2019, 10, 522–530, doi:10.3762/bjnano.10.53

• nitrogen or argon bubbling and/or freeze–pump–thaw cycles, the oxygen content can be lowered. These techniques are efficient enough to suppress the oxygen quenching of fluorescence [13]. The case of fluorescent samples containing dyes encapsulated in nanoconfined materials is more complicated. In general

• scattering than visible light, causes less photodamage, and can penetrate deeper into tissues. Hence, it is preferred for life-science applications. Organic dyes that can be excited above 600 nm are highly favorable for live-cell imaging experiments, because the background signal obtained from the

• the π-conjugated core system of highly fluorescent perylene-3,4:9,10-tetracarboxdimides. The rylene dyes have unique optical properties, such as high extinction coefficients, high thermal, chemical and photochemical stabilities, and exhibit brilliant colors [29][30]. Furthermore, in bulk samples, TDI

New micro/mesoporous nanocomposite material from low-cost sources for the efficient removal of aromatic and pathogenic pollutants from water

• Emmanuel I. Unuabonah,
• Robert Nöske,
• Jens Weber,
• Christina Günter and
• Andreas Taubert

Beilstein J. Nanotechnol. 2019, 10, 119–131, doi:10.3762/bjnano.10.11

• are reports of the use of clay/carbon materials for the removal of toxic micropollutants from water. In some cases, sugars have been used as starting compounds [17][18], while in other cases, dyes and other organic molecules have been loaded into the clay interlayer and calcined together with the clay

Electrolyte tuning in dye-sensitized solar cells with N-heterocyclic carbene (NHC) iron(II) sensitizers

• Mariia Karpacheva,
• Catherine E. Housecroft and
• Edwin C. Constable

Beilstein J. Nanotechnol. 2018, 9, 3069–3078, doi:10.3762/bjnano.9.285

• realized with ruthenium-based [2], zinc(II) porphyrin-based [5][6][7][8][9] or metal-free organic dyes [10][11][12]. In a recent review [2], Nazeeruddin points to the fact that only incremental enhancements of the photoconversion efficiencies of ruthenium dyes have occurred during the last two decades

• , with N3 (first reported in 1993 [13]) and N719 [14] (Scheme 1) remaining the state-of-the-art dyes. The low natural abundance of ruthenium (≈0.001 ppm in the Earth's crust [15]) and its consequential high cost motivates thorough investigations of the use of dyes based on Earth-abundant metals. Among

• . [21] have demonstrated the viability of DSCs comprising both copper(I)-based dyes and copper(I)/copper(II) redox shuttles. Photoconversion efficiencies in the range of 3–5% have been achieved for DSCs containing copper(I) dyes [22][23][24]. However, based upon the 800-fold greater natural abundance of

A novel polyhedral oligomeric silsesquioxane-modified layered double hydroxide: preparation, characterization and properties

• Xianwei Zhang,
• Zhongzhu Ma,
• Hong Fan,
• Carla Bittencourt,
• Jintao Wan and
• Philippe Dubois

Beilstein J. Nanotechnol. 2018, 9, 3053–3068, doi:10.3762/bjnano.9.284

• ][19], amino acids [20], anionic dyes [11], and compounds of biological origin, such as β-cyclodextrin and eugenol derivatives [9][10][13][21]. However, most of these current modifiers do not have satisfactory thermal stability and are flammable, reducing the thermal and fire stability of the LDHs

Low cost tips for tip-enhanced Raman spectroscopy fabricated by two-step electrochemical etching of 125 µm diameter gold wires

• Antonino Foti,
• Francesco Barreca,
• Enza Fazio,
• Cristiano D’Andrea,
• Paolo Matteini,
• Onofrio Maria Maragò and
• Pietro Giuseppe Gucciardi

Beilstein J. Nanotechnol. 2018, 9, 2718–2729, doi:10.3762/bjnano.9.254

• tested on dyes, pigments and biomolecules and enhancement factors higher than 105 are observed. TERS mapping with a spatial resolution of 5 nm is demonstrated. Keywords: amyloid; enhanced spectroscopy; gold tips; plasmonics; TERS; Introduction Tip-enhanced Raman spectroscopy (TERS) combines the

• times of approximately 2 min. The tips can be easily manipulated and safely mounted, by gluing or clamping them into STM- or ShF-based TERS setups. The good performance of the tips is highlighted by TERS spectra of dyes, pigments and biomolecules. The enhancement factor in the range of 104–105 was found

• on the shaft (red line). Typical laser powers are 1.0–2.5 mW and integration times are 0.5–1.0 s per pixel. TERS spectra of dyes, pigments and biomolecules The tips have been applied to evaluate the spectra of analyze standard dye molecules such as rhodamine 6G (R6G), crystal violet (CV), methylene

Nanocellulose: Recent advances and its prospects in environmental remediation

• Katrina Pui Yee Shak,
• Yean Ling Pang and
• Shee Keat Mah

Beilstein J. Nanotechnol. 2018, 9, 2479–2498, doi:10.3762/bjnano.9.232

• –OH of CNC. This modified nanocellulose adsorbent was used for the removal of cationic dyes from aqueous solution by forming a bidentate arrangement between the dye and the adsorbent’s carboxy groups. Meanwhile, Anirudhan et al. [92][93] modified a nanocellulose/nanobentonite composite adsorbent with

• displayed high uptake adsorption capacity for several cationic dyes such as methylene blue, basic fuchsin, crystal violet and malachite green [101]. Carboxylated CNC, with a high COOH content of 2.1 mmol/g, showed a significant uptake of about 769 mg/g for methylene blue as compared to CNC with surface

• nanocellulose materials were able to adsorb metal ions due to the presence of amino (–NH2) on aminosilane and/or –OH groups on cellulose fibre. Besides, cationic functionality such as amine-functionalized nanocellulose is usually effective for the removal of anionic dyes. Zhu et al. [102] found that

Hierarchical heterostructures of Bi₂MoO₆ microflowers decorated with Ag₂CO₃ nanoparticles for efficient visible-light-driven photocatalytic removal of toxic pollutants

• Shijie Li,
• Wei Jiang,
• Shiwei Hu,
• Yu Liu,
• Yanping Liu,
• Kaibing Xu and
• Jianshe Liu

Beilstein J. Nanotechnol. 2018, 9, 2297–2305, doi:10.3762/bjnano.9.214

• heterostructures exhibited substantially improved performance in the removal of industrial dyes (rhodamine B (RhB), methyl orange (MO), and methyl blue (MB)), and the antibiotic tetracycline hydrochloride (TC), compared with bare Bi2MoO6 and Ag2CO3 under visible-light irradiation. The enhancement of activity was

• candidate for wastewater treatment. Keywords: antibiotic removal; Bi2MoO6; heterojunction; silver carbonate (Ag2CO3); Introduction Industrial pollutants, such as industrial dyes and antibiotics, in wastewaters pose a huge threat to the environment [1][2]. Thus, many methods for pollutant removal have been

• the photocatalytic degradation of industrial dyes (rhodamine B (RhB), methyl orange (MO), and methyl blue (MB)), and the antibiotic tetracycline hydrochloride (TC) under visible light. The improved performance of the photocatalytic degradation was prominent, and the reasons were rationally analyzed

The role of adatoms in chloride-activated colloidal silver nanoparticles for surface-enhanced Raman scattering enhancement

• Nicolae Leopold,
• Andrei Stefancu,
• Krisztian Herman,
• István Sz. Tódor,
• Stefania D. Iancu,
• Vlad Moisoiu and
• Loredana F. Leopold

Beilstein J. Nanotechnol. 2018, 9, 2236–2247, doi:10.3762/bjnano.9.208

• reducing or capping agent. The resulting AgNPs are already SERS-activated by the Cl− ions chemisorbed onto the metal surface where the chloride concentration in the colloidal solution is 10−2 M. Consequently, the enhanced SERS spectra of cationic dyes (e.g., crystal violet or 9-aminoacridine) demonstrate

• -aminoacridine hydrochloride monohydrate were used as test analytes. Figure 4 shows comparatively the SERS spectra of the two cationic dyes obtained using the three silver colloids. By far, the Cl-AgNPs displayed the highest SERS intensity for both cationic dyes, followed by hya-AgNPs, which showed only low

• the case of cit-AgNPs which were previously activated by adding 1 mM NaCl (Figure 6C). In summary, high-intensity SERS spectra of cationic dyes can be recorded with all three silver colloids after activation. For this, our recommendation is that the silver colloid should contain Cl− anions in a

Dumbbell gold nanoparticle dimer antennas with advanced optical properties

• Janning F. Herrmann and
• Christiane Höppener

Beilstein J. Nanotechnol. 2018, 9, 2188–2197, doi:10.3762/bjnano.9.205

• , and retracting the antenna by 50 nm from the surface. The high quantum yield dyes Alexa633 and Alexa680 respectively, are applied for these measurements, which provide suitable absorption and emission properties in regard to the LSPR of the applied monomer and dimer AuNP antennas. Dark-field