Effects of surface functionalization on the adsorption of human serum albumin onto nanoparticles – a fluorescence correlation spectroscopy study

• Pauline Maffre,
• Stefan Brandholt,
• Karin Nienhaus,
• Li Shang,
• Wolfgang J. Parak and
• G. Ulrich Nienhaus

Beilstein J. Nanotechnol. 2014, 5, 2036–2047, doi:10.3762/bjnano.5.212

• with the charged NP surfaces [46]. The binding affinities were not governed by the net charge of the proteins (as specified by the isoelectric point) but rather by electrostatic interactions between localized charged regions on the protein and the NP surfaces [46]. An interesting temperature dependence

• monolayer arises if the HSA molecule adheres to the NP surface with one of its two large, triangular faces. We had suggested earlier that HSA adsorption is mediated by electrostatic interactions between a positively charged region on one of the large HSA faces (Figure 4a, red circle) and the negatively

• comparison with NPs coated with small thiolated ligands. For the zwitterionic, DPA-coated QDs, K′D = 0.31 ± 0.06 µM, the affinity is more than an order of magnitude higher than for DHLA-QDs, presumably because of the additional electrostatic interactions between carboxylic acid side chains on the protein and

Electrostatic interplay: The interaction triangle of polyamines, silicic acid, and phosphate studied through turbidity measurements, silicomolybdic acid test, and ²⁹Si NMR spectroscopy

• Anne Jantschke,
• Katrin Spinde and
• Eike Brunner

Beilstein J. Nanotechnol. 2014, 5, 2026–2035, doi:10.3762/bjnano.5.211

• charged for pH > 9.8. Hence, purely electrostatic interactions between the polyamine and monosilicic acid cannot be expected. In contrast to monosilicic acid, higher silicic acid oligomers/silica nanoparticles exhibit lower pKa values. For fumed silica, two different types of silanol groups are reported

• with pKa values of ca. 8 and 4.5 [46][47]. It can therefore be assumed that, in the relevant pH range of 5–7, the silica nanoparticles exhibit a negative surface charge. Electrostatic interactions will, therefore, occur between the positively charged polyamine and negatively charged higher silicic acid

• the sodium metasilicate solutions strongly enhances the absorbance at pH 6.8. That means the polyamine additive pronouncedly accelerates the aggregation process, which can be explained by the electrostatic interactions between the positively charged PAH and negative surface charges of higher silica

The surface properties of nanoparticles determine the agglomeration state and the size of the particles under physiological conditions

• Christoph Bantz,
• Olga Koshkina,
• Thomas Lang,
• Hans-Joachim Galla,
• C. James Kirkpatrick,
• Roland H. Stauber and
• Michael Maskos

Beilstein J. Nanotechnol. 2014, 5, 1774–1786, doi:10.3762/bjnano.5.188

• Debye-length scale is an important value describing the distance of electrostatic interactions between colloids. At physiological salt concentrations (at approximately 150 mM salinity), the Debye length is of the order of 0.8 nm (for symmetric electrolytes such as sodium chloride). This leads to

Controlling the dispersion of supported polyoxometalate heterogeneous catalysts: impact of hybridization and the role of hydrophilicity–hydrophobicity balance and supramolecularity

• Gijo Raj,
• Colas Swalus,
• Eglantine Arendt,
• Pierre Eloy,
• Michel Devillers and
• Eric M. Gaigneaux

Beilstein J. Nanotechnol. 2014, 5, 1749–1759, doi:10.3762/bjnano.5.185

• -based catalysts with enhanced processability, recoverability, and reusability. Organic–inorganic hybridization can be achieved either, through electrostatic interactions between POM anions and a polyampholyte polymer [15], or through covalent functionalization of POM anions with an organic moiety [16

• hybrids are deposited. For instance, surfactant-encapsulated clusters of POM anions, formed through electrostatic interactions, were reported to form well-ordered straight nanorods on graphite [17], whereas hybrid materials formed through covalent functionalization of POM formed planar layer-by-layer

Hydrophobic interaction governs unspecific adhesion of staphylococci: a single cell force spectroscopy study

• Nicolas Thewes,
• Peter Loskill,
• Philipp Jung,
• Henrik Peisker,
• Markus Bischoff,
• Mathias Herrmann and
• Karin Jacobs

Beilstein J. Nanotechnol. 2014, 5, 1501–1512, doi:10.3762/bjnano.5.163

• involved [26]. Since hydrophilic and hydrophobic Si wafers differ in composition only by a 2.6 nm thin OTS-monolayer on the surface, the van der Waals forces are nearly identical [13][27]. Forces due to electrostatic interactions between the negatively charged bacterium and the two types of wafer surfaces

• , which are both negatively charged (Table 1), are repulsive. Since the streaming potential is 20% more negative on the hydrophilic Si wafer, different electrostatic interactions give rise to a difference of adhesion forces of only a factor of 1.2, yet we record differences in the range of factors 10 to

The study of surface wetting, nanobubbles and boundary slip with an applied voltage: A review

• Yunlu Pan,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2014, 5, 1042–1065, doi:10.3762/bjnano.5.117

• protonation/deprotonation. The charged solid surface will lead to a layer in which ions are strongly attracted to the charged surface and do not move because of electrostatic interactions. Furthermore, there is another layer close to the surface called diffuse layer which is composed of ions that are

Energy transfer in complexes of water-soluble quantum dots and chlorin e6 molecules in different environments

• Irina V. Martynenko,
• Anna O. Orlova,
• Vladimir G. Maslov,
• Alexander V. Baranov,
• Anatoly V. Fedorov and
• Mikhail Artemyev

Beilstein J. Nanotechnol. 2013, 4, 895–902, doi:10.3762/bjnano.4.101

• dissipation occurs in all types of QD–Ce6 complexes and their contribution to the intracomplex energy transfer varies from 70% in covalently bonded complexes to ≈90% in complexes formed by electrostatic interactions and may be responsible for QD and Ce6 PL quenching. Electron transfer is the other possible

• electrostatic interactions in aqueous solution as a function of n. (a) Evolution of PL spectra of 5 nm QDs (dotted line) and sensibilized luminescence of Ce6 (solid line) extracted from PL spectra of the QD–Ce6 complexes. The PL excitation wavelength is 475 nm. The intensity of the Ce6 emission is multiplied by

Atomic force microscopy recognition of protein A on Staphylococcus aureus cell surfaces by labelling with IgG–Au conjugates

• Elena B. Tatlybaeva,
• Hike N. Nikiyan,
• Alexey S. Vasilchenko and
• Dmitri G. Deryabin

Beilstein J. Nanotechnol. 2013, 4, 743–749, doi:10.3762/bjnano.4.84

• B. licheniformis. Some of the observed labels (10%) were found on bacilli surfaces, which was undesirable for the selective labelling and discrimination of protein A-positive and -negative cells. We suppose that this was a nonspecific binding that can be explained by electrostatic interactions

Large-scale atomistic and quantum-mechanical simulations of a Nafion membrane: Morphology, proton solvation and charge transport

• Pavel V. Komarov,
• Pavel G. Khalatur and
• Alexei R. Khokhlov

Beilstein J. Nanotechnol. 2013, 4, 567–587, doi:10.3762/bjnano.4.65

• interaction terms (a Lennard–Jones "9-6" potential for the van der Waals interactions and a Coulombic term for electrostatic interactions). We used the same force field both for the neutral and the charged species (hydronium cations and sulfonic acid anions SO3−). For the neutral species, Coulomb interactions

• details are identical to those described in our work [27]. Integration step was 1 fs. A 12 Å cut-off radius was applied for Coulomb and van der Waals interactions. The electrostatic interactions were treated by using the PPPM method with a precision of 10−6. The dielectric constant was set to 1. All the

• extent determined by electrostatic interactions and directly related to ion pairing. The accepted mechanism of the ionic conductivity involves the mobile ions moving from one polymer chain to another by a chain-flexing process called segmental motion [77]. To clarify the issue of whether the driving

Molecular dynamics simulations of mechanical failure in polymorphic arrangements of amyloid fibrils containing structural defects

• Hlengisizwe Ndlovu,
• Alison E. Ashcroft,
• Sheena E. Radford and
• Sarah A. Harris

Beilstein J. Nanotechnol. 2013, 4, 429–440, doi:10.3762/bjnano.4.50

• understood by examining the intersheet interfaces that are affected during the SMD simulation. Both “slide” and “peel” modes disrupt the electrostatic interactions between the charged termini and force the hydrophobic core to be exposed to solvent molecules. For the three polymorphs containing eight peptides

• break suddenly because the interactions stabilising the fibrils (hydrogen bonding and hydrophobic forces) are short-ranged in comparison to the long-range electrostatic interactions within the uncapped fibrils. This highlights how a relatively simple modification at the terminus end can have a

• molecules [39] with periodic boundary conditions applied in all three directions. As the peptide sequence carried no net charge, neutralisation with counter-ions was not necessary. Long-range electrostatic interactions were calculated using the particle mesh Ewald (PME) method with a 9 Å cut-off. The models

Selective surface modification of lithographic silicon oxide nanostructures by organofunctional silanes

• Thomas Baumgärtel,
• Christian von Borczyskowski and
• Harald Graaf

Beilstein J. Nanotechnol. 2013, 4, 218–226, doi:10.3762/bjnano.4.22

• fluorescence signal is comparably weak (roughly a factor of 10 above the background noise level). The main reason for this is the quenching by the underlying silicon. Nevertheless, other high-quantum-yield xanthene dyes (e.g., rhodamine 6G) that are bound to the nanostructures by electrostatic interactions

FTIR nanobiosensors for Escherichia coli detection

• Stefania Mura,
• Gianfranco Greppi,
• Maria Laura Marongiu,
• Pier Paolo Roggero,
• Sandeep P. Ravindranath,
• Lisa J. Mauer,
• Nicoletta Schibeci,
• Francesco Perria,
• Massimo Piccinini,
• Plinio Innocenzi and
• Joseph Irudayaraj

Beilstein J. Nanotechnol. 2012, 3, 485–492, doi:10.3762/bjnano.3.55

• to entrap pathogens with electrostatic interactions not differentiating between pathogens. Determination of the detection limits of E. coli O157:H7 Tests to establish the detection limit of the device were carried out using serial dilutions of E. coli ranging in concentration from 1 × 108 CFU/mL to

• and K12) on a titania thin film (Figure 5a), on films with only the specific antibody for E. coli O157:H7, and on films with APTES and Ab (Figure 5c) were tested. Figure 5a shows the FTIR spectra of different strains of E. coli (O157:H7 and K12) adsorbed onto the film surface with electrostatic

• interactions, illustrating that the substrate cannot discriminate between different strains and the different spectra of the pathogens are clearly visible. In contrast, in films with specific antibodies, only the binding of E. coli O157:H7 was visible and is reported in Figure 5b and 5c, although in films with

Macromolecular shape and interactions in layer-by-layer assemblies within cylindrical nanopores

• Thomas D. Lazzara,
• K. H. Aaron Lau,
• Wolfgang Knoll,
• Andreas Janshoff and
• Claudia Steinem

Beilstein J. Nanotechnol. 2012, 3, 475–484, doi:10.3762/bjnano.3.54

• negatively charged surface, followed by b-BSA (MW = 67 kDa) adsorption through molecular recognition. Linear-polyelectrolytes (linear-PEs) self-assembled into multilayers by electrostatic interactions between 70 kDa poly(sodium 4-styrene sulfonate) (PSS) and 50–65 kDa poly(allyl amine) hydrochloride (PAH

• charged surfaces [46][47][48]. Furthermore, polyelectrolyte films are dynamic self-assemblies, in the sense that the internal structure of the film can undergo rearrangements to achieve optimal packing density due to flexible electrostatic interactions. Furthermore, it is expected that the high degree of

An NC-AFM and KPFM study of the adsorption of a triphenylene derivative on KBr(001)

• Antoine Hinaut,
• Adeline Pujol,
• Florian Chaumeton,
• David Martrou,
• André Gourdon and
• Sébastien Gauthier

Beilstein J. Nanotechnol. 2012, 3, 221–229, doi:10.3762/bjnano.3.25

• molecules on this type of surface is dominated by van der Waals and electrostatic interactions, and that the charge transfer between the substrate and the molecule is negligible [39]. The KBr slab was composed of 6 × 6 × 3 unit cells. Two KBr layers were free to relax during the simulations. (a) Molecular

Molecular-resolution imaging of pentacene on KCl(001)

• Julia L. Neff,
• Jan Götzen,
• Enhui Li,
• Michael Marz and
• Regina Hoffmann-Vogel

Beilstein J. Nanotechnol. 2012, 3, 186–191, doi:10.3762/bjnano.3.20

• molecules with the substrate is much weaker than on metals because the partial transfer of electrons is expected to be weak, such that the interaction is dominated by van der Waals and electrostatic interactions, as opposed to chemical bonding. A unique tool to investigate the thin-film structure of

X-ray spectroscopy characterization of self-assembled monolayers of nitrile-substituted oligo(phenylene ethynylene)s with variable chain length

• Hicham Hamoudi,
• Ping Kao,
• Alexei Nefedov,
• David L. Allara and
• Michael Zharnikov

Beilstein J. Nanotechnol. 2012, 3, 12–24, doi:10.3762/bjnano.3.2

• contrast to the aliphatic NC-terminated SAMs in which the introduction of the nitrile tail group results in a significant disturbance of the molecular orientation and orientational order [54]. This disturbance can be understood in terms of the strong electrostatic interactions between the nitrile groups

Investigation on structural, thermal, optical and sensing properties of meta-stable hexagonal MoO₃ nanocrystals of one dimensional structure

• Angamuthuraj Chithambararaj and
• Arumugam Chandra Bose

Beilstein J. Nanotechnol. 2011, 2, 585–592, doi:10.3762/bjnano.2.62

• (aq) + 6 HNO3 → 7 MoO3 (s) + 6 NH4NO3 (aq) + 7 H2O Here, molybdenum is located at the center and six oxygen atoms are coordinated in octahedral sites. During the nucleation, these octahedral structures interact with each other through corners (a-axis) and edges (c-axis) by means of electrostatic

• interactions between NH4+ and OH− ions. The stacking and assembling of these octahedral structures result in the formation of a stable hexagonal structure. Thus, the NH4+ functional group present in the reaction condition acts indirectly as a structure directing agent [4][23]. Moreover, the initial seed nuclei

Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

• Miriam Jaafar,
• Oscar Iglesias-Freire,
• Luis Serrano-Ramón,
• Manuel Ricardo Ibarra,
• Jose Maria de Teresa and
• Agustina Asenjo

Beilstein J. Nanotechnol. 2011, 2, 552–560, doi:10.3762/bjnano.2.59

• electrostatic interactions are not compensated, an incorrect interpretation of the MFM could be made. This is especially problematic in samples with low magnetic moment where it is crucial to distinguish clearly the origin of the interaction for a correct interpretation of the results [10]. Results and

• proportional to the total force gradient (that can be composed of magnetic and/or electrostatic interactions). The experiments in the present work were performed in ambient conditions, in the non-contact dynamic mode (with low amplitude modulation) and with the PLL feedback activated. In addition, KPFM [17

• based materials [10][11]. In general, these materials present low magnetic moment at room temperature. In addition, since the substrate and the nanomagnets present quite different electronic behavior, the sample can exhibit large surface potential differences, which cause heterogeneous electrostatic

Microfluidic anodization of aluminum films for the fabrication of nanoporous lipid bilayer support structures

• Jaydeep Bhattacharya,
• Alexandre Kisner,
• Andreas Offenhäusser and
• Bernhard Wolfrum

Beilstein J. Nanotechnol. 2011, 2, 104–109, doi:10.3762/bjnano.2.12

• . Vesicle rupture is probably aided via electrostatic interactions of the negative phosphate of the zwitterionic POPC-heads with the protonated amino groups from the APTES molecules immobilized on the surface [42]. In principle, one could also expect coverage of the inside pore walls, as has been observed

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

• of the dynamical processes occurring during manipulation, i.e., collisions between probing tips and particles, friction between particles and substrates, electrostatic interactions among all of them, etc. For this reason, colloidal particles have appeared as model nano-objects because they can be

• is essentially affected by electrostatic interactions arising from residues from the synthesis (citric acid) that may be adsorbed on the particles. It is thus normal, in the absence of both physical contact and notable intermolecular forces between the particles, that their mobility is independent of

Single-pass Kelvin force microscopy and dC/dZ measurements in the intermittent contact: applications to polymer materials

• Sergei Magonov and
• John Alexander

Beilstein J. Nanotechnol. 2011, 2, 15–27, doi:10.3762/bjnano.2.2

• directly from the photodetector (AM–AM) or from the LIA-1 (AM–FM). The latter block scheme configuration is shown in Figure 1. In the AM–FM, the electrostatic interactions are excited by an AC voltage applied to the probe at ωelec = 3–5 kHz, which is within the bandwidth of ωmech. The electrostatic

• corresponding to the transition to the intermittent contact regime. The topography image recorded in the non-contact mode is practically featureless. At the conditions near the transition, it may be possible to detect weak cross-talk patterns, which are caused by the long-distance electrostatic interactions

• Sergei Magonov John Alexander Agilent Technologies, 4330 Chandler Blvd., Chandler, AZ 85226, U.S.A. 10.3762/bjnano.2.2 Abstract We demonstrate that single-pass Kelvin force microscopy (KFM) and capacitance gradient (dC/dZ) measurements with force gradient detection of tip–sample electrostatic