Colorimetric detection of Cu²⁺ based on the formation of peptide–copper complexes on silver nanoparticle surfaces

• Gajanan Sampatrao Ghodake,
• Surendra Krishna Shinde,
• Rijuta Ganesh Saratale,
• Avinash Ashok Kadam,
• Ganesh Dattatraya Saratale,
• Asad Syed,
• Fuad Ameen and
• Dae-Young Kim

Beilstein J. Nanotechnol. 2018, 9, 1414–1422, doi:10.3762/bjnano.9.134

• stability to the AgNP dispersions. The absorbance signal at 410 nm linearly decreased with increasing concentration of diluted HCl from 0.1 to 0.6 mM and then further declined in the presence of Cu2+. The extreme decrease in absorbance of AgNPs triggered by Cu2+ addition, even in the presence of 0.1 mM HCl

• , stable dispersions of AgNPs could be formed through interactions with OH− ions [25], which inhibit the formation of AgNPs aggregates in the presence of Cu2+. Instead, in the present study, stable sensitivity occurred under alkaline pH conditions, possibly through the formation of various coordination

Robust midgap states in band-inverted junctions under electric and magnetic fields

• Álvaro Díaz-Fernández,
• Natalia del Valle and
• Francisco Domínguez-Adame

Beilstein J. Nanotechnol. 2018, 9, 1405–1413, doi:10.3762/bjnano.9.133

• . A two-band model within the envelope-function approximation predicts the appearance of midgap interface states with Dirac cone dispersions in band-inverted junctions, namely, when the gap changes sign along the growth direction. We present a thorough study of these interface electron states in the

• the band edge due to the bending by the electric field (see main text for details). First Landau level dispersions for b = 0.5 and f =0.499. In panel (a), the original parabolic dispersion along the y-direction splits into two parabolic dispersions with energies below the band edge for the chosen

Optimisation of purification techniques for the preparation of large-volume aqueous solar nanoparticle inks for organic photovoltaics

• Furqan Almyahi,
• Thomas R. Andersen,
• Nathan A. Cooling,
• Natalie P. Holmes,
• Matthew J. Griffith,
• Krishna Feron,
• Xiaojing Zhou,
• Warwick J. Belcher and
• Paul C. Dastoor

Beilstein J. Nanotechnol. 2018, 9, 649–659, doi:10.3762/bjnano.9.60

• to renew the solvent and continue separation makes this technique impractical for large scale material preparation. In an earlier study, ASNP inks with large volume (100 mL) from 500 mL dispersions were prepared, with the purification of ASNPs from excess-surfactant conducted using a commercial

• ). As a fourth step, removal of chloroform was conducted at 65 °C and 1200 rpm for 4 h to produce aqueous nanoparticle P3HT:ICxA dispersions (≈500 g). The final step is the ultrafiltration process to remove excess surfactant using two types of purification methods, and to concentrate to 6 wt % solids

• identical initial dilution and completed with an identical volume to provide a constant dilution factor. The initial volume of ASNP dispersions were 250 mL or 2.5 mL for inks purified by the crossflow and centrifugal ultrafiltration processes, respectively. In any single filtration step, these volumes were

Facile phase transfer of gold nanorods and nanospheres stabilized with block copolymers

• Yaroslav I. Derikov,
• Georgiy A. Shandryuk,
• Raisa V. Talroze,
• Alexander A. Ezhov and
• Yaroslav V. Kudryavtsev

Beilstein J. Nanotechnol. 2018, 9, 616–627, doi:10.3762/bjnano.9.58

• enhance sensitivity of amphiphilic dispersions to external stimuli. Block copolymers are effective for the phase transfer of spherical Au nanoparticles up to 30 nm in diameter from aqueous to organic phases [29][35][36]. The tendency for aggregation is increased when the block interacting with the

Ultralight super-hydrophobic carbon aerogels based on cellulose nanofibers/poly(vinyl alcohol)/graphene oxide (CNFs/PVA/GO) for highly effective oil–water separation

• Zhaoyang Xu,
• Huan Zhou,
• Sicong Tan,
• Xiangdong Jiang,
• Weibing Wu,
• Jiangtao Shi and
• Peng Chen

Beilstein J. Nanotechnol. 2018, 9, 508–519, doi:10.3762/bjnano.9.49

• recorded in detail in our previous research paper [40]. Then, we obtained exfoliated single-layered GO sheets in GO aqueous dispersions under ultrasonication at 80 kHz for 2 h. Preparation of poly(vinyl alcohol) solution PVA (5.0 g) was dissolved in deionized water (100 mL) with continuous stirring for 4 h

Liquid-crystalline nanoarchitectures for tissue engineering

• Baeckkyoung Sung and
• Min-Ho Kim

Beilstein J. Nanotechnol. 2018, 9, 205–215, doi:10.3762/bjnano.9.22

• for applying LC nanoarchitectures to tissue regeneration purposes is discussed. Liquid crystalline phases of biological polymers and colloids in vitro Geometry in biological LCs Lyotropic LC phases are observed in the aqueous dispersions of various types of biological rod-like building blocks, such as

• -compatible subcutaneous implant [108]. Synthetic substrates, membranes, and dispersions in other LC geometries Smectic-like and columnar-like architectures can be also adopted as nanostructures for tissue engineering and regenerative medicine. Lamellar templates in the smectic phase with spiral dislocation

• dispersions in various phases (e.g., lamellar, hexagonal, reverse hexagonal, bicontinuous cubic, micellar cubic) have been investigated in terms of the physicochemical interactions between stratum corneum and the LC formulations for pharmaceutic purposes [112][113]. Conclusion The strength of LC biomaterials

The role of ligands in coinage-metal nanoparticles for electronics

• Ioannis Kanelidis and
• Tobias Kraus

Beilstein J. Nanotechnol. 2017, 8, 2625–2639, doi:10.3762/bjnano.8.263

• shapes; they also affect size and colloidal stability. Particle shapes can be tuned via the ligand choice while ligand length, size, ω-functionalities, and chemical nature influence shelf-life and stability of nanoparticles in dispersions. When particles are deposited, ligands affect the electrical

• printing processes [32][33]. Certain ligands mediate the formation of nanoparticles directly in an ink precursor, thus unifying nanoparticle and ink preparation [25]. The interparticle spacing induced by the ligands helps to stabilize the dispersions, but it also causes insulating barriers after deposition

• colloidal dispersions The stability of colloidal dispersions depends on the capping ligands and affects shelf life and performance [32]. Ligands can trigger or prevent the agglomeration of metal nanoparticles depending on the solvent [81][82]. Ligand exchange may be necessary after synthesis to enable

Synthesis of metal-fluoride nanoparticles supported on thermally reduced graphite oxide

• Alexa Schmitz,
• Kai Schütte,
• Vesko Ilievski,
• Juri Barthel,
• Laura Burk,
• Rolf Mülhaupt,
• Junpei Yue,
• Bernd Smarsly and
• Christoph Janiak

Beilstein J. Nanotechnol. 2017, 8, 2474–2483, doi:10.3762/bjnano.8.247

• decomposition by microwave irradiation of the precursors in IL was achieved after only 10 min for Co(II) and 15 min for Fe(II), Eu(III) and Pr(III) using a low power of 50 W to give a temperature of 220 °C in the reaction mixture (Scheme 1). Black dispersions of nanocomposite materials were reproducibly

• S4–S19 in Supporting Information File 1) indicated the formation of MFx nanoparticles with typical diameters between 4 and 30 nm supported on the TRGO. The sizes and size dispersions of the metal-fluoride nanoparticles are summarized in Table 1. The diameters of the MFx nanoparticles were derived

• in Supporting Information File 1. The PXRDs for the other samples are given in Figures S4–S19 in Supporting Information File 1. TEM images of PrF3@TRGO-400 dispersions from [Pr(AMD)3] in [BMIm][BF4]. XPS of PrF3@TRGO-400 dispersions from [Pr(AMD)3] in [BMIm][BF4]. The electrochemical performance of

High-stress study of bioinspired multifunctional PEDOT:PSS/nanoclay nanocomposites using AFM, SEM and numerical simulation

• Alfredo J. Diaz,
• Hanaul Noh,
• Tobias Meier and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 2069–2082, doi:10.3762/bjnano.8.207

• ]) are added, PEDOT:PSS undergoes a structure rearrangement that results in a morphology that favors electron conduction. The nanoclay dispersions have the potential to modify the morphology of the polymer by secondary interactions due to the nanoclay charge, sodium cations and hydrophobicity, thus

• and establish structure-functionality relations for advanced functional materials. Methods Sample preparation Nanoclay dispersions with 0.5 wt % of Laponite RD (LAP) or Cloisite Na+ (montmorillonite, MTM), both from Rockwood Industries, were prepared in deionized water (DI-H2O) and stirred for 24 h at

• 1500 RPM. The dispersions were decanted for a few days to remove large particles. The thickness of individual nanoclays was found to be approximately 1 nm, as shown in Supporting Information File 1, Figures S9 and S10. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS, Sigma-Aldrich

A comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively or negatively charged nanodiamonds

• Colin K. Curtis,
• Antonin Marek,
• Alex I. Smirnov and
• Jacqueline Krim

Beilstein J. Nanotechnol. 2017, 8, 2045–2059, doi:10.3762/bjnano.8.205

• very high (1011 cm−2) for oxidized nanodiamonds (−ND) on AlN substrates [47]. The data are also consistent with a report on a formation of ND clusters of ca. 23 nm in diameter on SiO2 surfaces exposed to ND dispersions [48]. Clusters of this size are large enough to separate the surfaces employed for

• Figure 7. All QCM crystals were first exposed in DI water for 1 h followed by +ND or −ND dispersions for another 1 h and then returned to DI water for an additional 1 h. Fluid injections at 1 and 2 h in some cases caused temporary perturbations in f and R that serve as markers delineating the three

• data reported here reveal key similarities and differences in both the macro- and nanotribological properties of stainless steel and alumina when exposed to ND aqueous dispersions. While Liu et al.’s suggestion that −ND dispersions are more likely to improve the tribological performance at the

Fabrication of carbon nanospheres by the pyrolysis of polyacrylonitrile–poly(methyl methacrylate) core–shell composite nanoparticles

• Dafu Wei,
• Youwei Zhang and
• Jinping Fu

Beilstein J. Nanotechnol. 2017, 8, 1897–1908, doi:10.3762/bjnano.8.190

• at a concentration of 1.0 g/L. Then, the dispersions were left to stand overnight. The carbonized product of the PAN nanoparticles remained settled at the bottom of the bottle during the ultrasonic treatment (Supporting Information File 1, Figure S6a), indicating the strong adhesion between the

• -based nanoparticles determined by TEM and DLS; Photograph of preoxidized products of PAN-PMMA2 nanoparticles; TG curve of PMMA nanoparticles; Photograph of acetone dispersions of carbonized products after overnight storage; TEM micrographs of carbonized products of shell-crosslinked PAN-cPMMA2

A biofunctionalizable ink platform composed of catechol-modified chitosan and reduced graphene oxide/platinum nanocomposite

• Peter Sobolewski,
• Agata Goszczyńska,
• Małgorzata Aleksandrzak,
• Karolina Urbaś,
• Joanna Derkowska,
• Agnieszka Bartoszewska,
• Jacek Podolski,
• Ewa Mijowska and
• Mirosława El Fray

Beilstein J. Nanotechnol. 2017, 8, 1508–1514, doi:10.3762/bjnano.8.151

• modified the chitosan with catechol groups, in order to obtain adhesive properties and improve solubility. Dispersions of rGO–Pt in ethylene glycol were admixed with an aqueous solution of modified chitosan to yield an ink that is suitable for non-contact piezoelectric printing using a commercial

• . First, we prepare dispersions of reduced graphene oxide (rGO) decorated with platinum nanoparticles (rGO–Pt) in ethylene glycol (EG). As the polymer matrix, we utilize chitosan (CHI), a polycationic biopolymer that provides excellent film-forming properties and easy-to-functionalize amine groups [8

• ]. However, we first chemically modify the chitosan to add catechol pendant groups to the chitosan polymer chains [9], in order to improve water solubility, as well as provide adhesive properties to a variety of substrates [10]. The ink is formed by admixing rGO–Pt dispersions in ethylene glycol with the

Calcium fluoride based multifunctional nanoparticles for multimodal imaging

• Marion Straßer,
• Joachim H. X. Schrauth,
• Sofia Dembski,
• Daniel Haddad,
• Bernd Ahrens,
• Stefan Schweizer,
• Bastian Christ,
• Alevtina Cubukova,
• Marco Metzger,
• Heike Walles,
• Peter M. Jakob and
• Gerhard Sextl

Beilstein J. Nanotechnol. 2017, 8, 1484–1493, doi:10.3762/bjnano.8.148

• end, different NP samples dispersed in water were characterized by MRI. To determine the contrast effect, NP dispersions of various concentrations (0.4–18.2 mg·mL−1) were analyzed. CaF2:(Tb3+,Gd3+) NPs as MRI contrast agent Doping with Gd3+ ions leads to paramagnetism of the CaF2 NPs. Because of this

• relaxation rates from our NP dispersions with the relaxation rate from Magnevist we should convert the units because Magnevist is a complex with only one Gd3+ ion. In contrast, there are many Gd3+ ions in one NP evoking the MR activity. Unfortunately, we cannot quantify by now the exact amount of Gd3+ ions

• decreases within 2 h because of light scattering on NP agglomerates. Light-microscopy images of dispersions of stabilized and non-stabilized CaF2:(Tb3+,Gd3+) NPs in FCS-containing cell-culture medium are given in Figure S3 (Supporting Information File 1). Finally, the viability of human dermal fibroblasts

Development of polycationic amphiphilic cyclodextrin nanoparticles for anticancer drug delivery

• Gamze Varan,
• Juan M. Benito,
• Carmen Ortiz Mellet and
• Erem Bilensoy

Beilstein J. Nanotechnol. 2017, 8, 1457–1468, doi:10.3762/bjnano.8.145

• month in aqueous form to determine the physical stability of PCX-loaded amphiphilic CD nanoparticle dispersions. Figure 2, Figure 3 and Figure 4 show that there is no significant difference for particle size, PDI and zeta potential of PCX-loaded and blank CD nanoparticle formulations (p > 0.05). PCX

• nanoparticles as well as drug entrapped per unit polymer. The in vitro cumulative release profile of PCX from CD nanoparticles was determined with the dialysis membrane technique under sink conditions in a shaking water bath at 37 °C in PBS pH 7.4. Briefly, drug-loaded nanoparticle dispersions were added in the

• nanoparticles were stored in ultrapure water at 4 °C and the mean particle size, PDI values and zeta potential were obtained periodically for 30 days in aqueous dispersion form to elucidate whether PCX crystals are formed or any aggregation/precipitation is observed upon storage of the nanoparticle dispersions

Cationic PEGylated polycaprolactone nanoparticles carrying post-operation docetaxel for glioma treatment

• Cem Varan and
• Erem Bilensoy

Beilstein J. Nanotechnol. 2017, 8, 1446–1456, doi:10.3762/bjnano.8.144

• than 100 nm and a net positive surface charge to facilitate cellular internalization of drug-loaded nanoparticles. Hydroxypropyl cellulose films were prepared to incorporate these nanoparticle dispersions to complete the implantable drug delivery system. Results: The diameter of core–shell

• mePEG-PCL nanoparticles increased by 13–23 nm during this period. However, this increase is not statistically significant. Consequently, it can be said that aqueous dispersions of drug-loaded nanoparticles are physically stable for a period of 1 month. Encapsulation efficacy of drug-loaded nanoparticles

• that all formulations are safe for in vivo application, regardless of dose or time. Anticancer efficacy of docetaxel-loaded nanoparticles The anticancer efficacy of drug-loaded nanoparticle dispersions were determined on rat glioma cell line RG2. As seen in Figure 7, anticancer efficiency is enhanced

Low uptake of silica nanoparticles in Caco-2 intestinal epithelial barriers

• Dong Ye,
• Mattia Bramini,
• Delyan R. Hristov,
• Sha Wan,
• Anna Salvati,
• Christoffer Åberg and
• Kenneth A. Dawson

Beilstein J. Nanotechnol. 2017, 8, 1396–1406, doi:10.3762/bjnano.8.141

• stocks were cleaned (by pelleting and resuspending in fresh buffer) prior to experiments with cells. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that for both nanoparticles, no labile dye was present in the nanoparticle dispersions (Supporting Information File 1

• , with no signs of agglomeration, though naturally serum protein adsorption increases the sizes. Table 1 also shows auxiliary dispersion characterisation by dynamic light scattering (DLS), leading to the same conclusions. Nanoparticle dispersions were prepared with and without FBS protein in order to

• effects of bioaccumulation over chronic exposure. Experimental Nanoparticle characterisation Green fluorescently labelled SiO2-NPs of 50 and 150 nm diameters were synthesized in house according to previous literature [42]. Particle dispersions were characterised at 100 µg/mL in 0% and 10% foetal bovine

3D continuum phonon model for group-IV 2D materials

• Morten Willatzen,
• Lok C. Lew Yan Voon,
• Appala Naidu Gandi and
• Udo Schwingenschlögl

Beilstein J. Nanotechnol. 2017, 8, 1345–1356, doi:10.3762/bjnano.8.136

• acoustic modes with linear dispersions and out-of-plane transverse acoustic modes with quadratic dispersions (the latter being consistent with the elastic theory of thin plates) to construct either a Lagrangian [10] or equations of motion [11]. Goupalov also considered optical phonons but simply

• coordinate in the analysis to reveal the true phonon dispersions as observed experimentally and in DFT calculations. The general 3D elastic equations are given by the equation of motion [14] where Tik is the stress tensor, ρ is the mass density, and ui is the displacement. Equation 1 contains all the physics

• -centered 24 × 24 × 1 k-meshes. A direct method based on 4 × 4 × 1 supercells is used for obtaining the phonon dispersions within the harmonic approximation [20]. Forces are evaluated on 3 × 3 × 1 k-meshes, including long-range dipole contributions to the dynamical matrix following the method of [21]. Born

Miniemulsion copolymerization of (meth)acrylates in the presence of functionalized multiwalled carbon nanotubes for reinforced coating applications

• Bertha T. Pérez-Martínez,
• Lorena Farías-Cepeda,
• Víctor M. Ovando-Medina,
• José M. Asua,
• Lucero Rosales-Marines and
• Radmila Tomovska

Beilstein J. Nanotechnol. 2017, 8, 1328–1337, doi:10.3762/bjnano.8.134

• technology (blends of latexes and CNT dispersions) [13][14][15][16][17], and in situ polymerization [8][12][18][19][20][21]. In situ polymerization can be performed in solution, bulk and in dispersed media. Polymerization in dispersed media allows a relatively easy control of the reactor temperature (which

• surfactant on the kinetics of miniemulsion polymerization of butyl acrylate (BA) in the presence of CNTs. Waterborne polymer dispersions are mainly used for coatings and adhesives, which involve the formation of films directly cast from the dispersion, usually at ambient temperature [22][24]. This limits the

• potential application of the dispersions prepared in the works discussed above [18][32][33][34] because high glass transition temperature (Tg) polymers that do not form films at ambient temperature were synthesized. From BA dispersions, the adhesive films might eventually be prepared; however, Capek and

Carbon nanomaterials sensitize prostate cancer cells to docetaxel and mitomycin C via induction of apoptosis and inhibition of proliferation

• Kati Erdmann,
• Jessica Ringel,
• Silke Hampel,
• Manfred P. Wirth and
• Susanne Fuessel

Beilstein J. Nanotechnol. 2017, 8, 1307–1317, doi:10.3762/bjnano.8.132

• , USA). The physico-chemical properties of both carbon nanomaterials have been determined previously [13][28] and are summarized in Table 4. Chemotherapeutics were provided by the in-house pharmacy (University Hospital, Dresden, Germany). Dispersions of the carbon nanomaterials were freshly prepared as

Bright fluorescent silica-nanoparticle probes for high-resolution STED and confocal microscopy

• Isabella Tavernaro,
• Christian Cavelius,
• Henrike Peuschel and
• Annette Kraegeloh

Beilstein J. Nanotechnol. 2017, 8, 1283–1296, doi:10.3762/bjnano.8.130

• particle dispersions were diluted 1:10 in MilliQ water. Measurements were performed at room temperature. Each sample was measured three times with at least three runs (3 min/run). The mean hydrodynamic diameter was determined by using the cumulants analysis and a size distribution using a regularization

AgCl-doped CdSe quantum dots with near-IR photoluminescence

• Pavel A. Kotin,
• Sergey S. Bubenov,
• Natalia E. Mordvinova and
• Sergey G. Dorofeev

Beilstein J. Nanotechnol. 2017, 8, 1156–1166, doi:10.3762/bjnano.8.117

• with a Varian Cary 50 spectrophotometer from 300 to 1100 nm. The fluorescence was measured with 405 nm laser excitation and detected by an Ocean Optics USB 4000 spectrometer calibrated by a 2600 K W-lamp (450–1100 nm). The energy QYs were determined in diluted dispersions relative to rhodamine 6G

Preparation of thick silica coatings on carbon fibers with fine-structured silica nanotubes induced by a self-assembly process

• Benjamin Baumgärtner,
• Hendrik Möller,
• Thomas Neumann and
• Dirk Volkmer

Beilstein J. Nanotechnol. 2017, 8, 1145–1155, doi:10.3762/bjnano.8.116

• dispersions leads to a non-exhaustive coating of the surface. For a more or less complete surface coating, the fiber density in the dispersion should not exceed 1.5 g/L. This challenge and a potential interlocking of silicified fibers are insignificant for a coating process of carbon fiber felts. An activated

α-((4-Cyanobenzoyl)oxy)-ω-methyl poly(ethylene glycol): a new stabilizer for silver nanoparticles

• Jana Lutze,
• Miguel A. Bañares,
• Marcos Pita,
• Andrea Haase,
• Andreas Luch and
• Andreas Taubert

Beilstein J. Nanotechnol. 2017, 8, 627–635, doi:10.3762/bjnano.8.67

• essential to obtain and retain stable particle dispersions [11][14][15][16]. Synthetic particles often have coatings made from polymers such as poly(vinyl pyrrolidone), poly(vinyl alcohol), or poly(ethylene glycol) (PEG). PEG-based coatings are particularly popular [17][18]. This is also due to the high

• ) for samples incubated in dispersions with a pH of 12. In contrast, the zeta potentials measured for samples treated at lower pH are around −20 to −30 mV. Unlike the zeta potential, the hydrodynamic radius Rh (as determined by DLS) remains the same at all pH values and over the entire time of

• distributions. DLS sometimes detects bimodal size distributions and in other cases monomodal but very broad distributions. This is also reflected in the rather large deviations from the mean value of Rh (Table 1) and is consistent with the UV–vis spectra (Figure 2). Discussion Stable nanoparticle dispersions

Investigation of the photocatalytic efficiency of tantalum alkoxy carboxylate-derived Ta₂O₅ nanoparticles in rhodamine B removal

• Subia Ambreen,
• Mohammad Danish,
• Narendra D. Pandey and
• Ashutosh Pandey

Beilstein J. Nanotechnol. 2017, 8, 604–613, doi:10.3762/bjnano.8.65

• nanoparticles samples are found to be in the range of 120–170 nm. The oxide nanoparticles are moderately evenly dispersed in all cases. DLS measurements To study the properties of nanoparticles in dispersion dynamic light scattering (DLS) experiments were carried out. Stable dispersions of Ta2O5 nanoparticles

• in chloroform were prepared by using the surfactant trioctylphosphine oxide (TOPO). TOPO molecules provide stability and uniformity to the nanoparticles in chloroform. Table 2 shows the obtained particle sizes and distributions of Ta2O5 in chloroform dispersions. It can be seen that the TOPO-coated

Performance of colloidal CdS sensitized solar cells with ZnO nanorods/nanoparticles

• Anurag Roy,
• Partha Pratim Das,
• Mukta Tathavadekar,
• Sumita Das and
• Parukuttyamma Sujatha Devi

Beilstein J. Nanotechnol. 2017, 8, 210–221, doi:10.3762/bjnano.8.23

• analysis, as shown in Figure 3b. Further investigation of contact angle (CA) measurements by using CdS dispersions on ZnO-based films justifies the sensitization capability. The reduced CA value of 19.6° for the film fabricated with ZnO-P further ascertains its better CdS affinity whereas a moderate CA