Microbubbles decorated with dendronized magnetic nanoparticles for biomedical imaging: effective stabilization via fluorous interactions

• Da Shi,
• Justine Wallyn,
• Dinh-Vu Nguyen,
• Francis Perton,
• Delphine Felder-Flesch,
• Sylvie Bégin-Colin,
• Mounir Maaloum and
• Marie Pierre Krafft

Beilstein J. Nanotechnol. 2019, 10, 2103–2115, doi:10.3762/bjnano.10.205

• conjunction with focused ultrasound, and under magnetic resonance imaging guidance, for achieving blood/brain and blood/tumor barrier crossing of drugs [11][12]. Medical MBs have a shell consisting of surfactants, phospholipids, or polymers and are usually stabilized by a fluorocarbon gas [13] that acts as an

• MBs that incorporate IONPs are often made of polymers. For example, ultrasmall superparamagnetic iron oxide nanoparticles were embedded in the wall of poly(butyl cyanoacrylate)-based MBs, allowing the blood‒brain barrier penetration to be monitored [23]. Soft-shell colloids called lipospheres have

Ion mobility and material transport on KBr in air as a function of the relative humidity

• Dominik J. Kirpal,
• Korbinian Pürckhauer,
• Alfred J. Weymouth and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2019, 10, 2084–2093, doi:10.3762/bjnano.10.203

• changes from the first state into the second state and from the second state into the first state, attaching to the hole. These transitions require each atom to overcome an energy barrier Eb. The change rate can be expressed by with N being the size of the observed structure, ν the attempt frequency to

• overcome the energy barrier, kB the Boltzmann constant and T the temperature. We assume an attempt rate of ν = 1013 s−1, which is in the order of magnitude of a KBr phonon [31], equal for both transitions. This differential equation can be solved by an exponential decaying function of the form N(t) = N0

• ·exp(−t/τ), with N0 being the structure size at the time t = 0 (in this case the time after the initial enhanced transport) and 1/τ the exponential decay rate. This allows us to calculate a value for the energy barrier from the recorded data, given by As we consider the exponential decay rate to be

First principles modeling of pure black phosphorus devices under pressure

• Ximing Rong,
• Zhizhou Yu,
• Zewen Wu,
• Junjun Li,
• Bin Wang and
• Yin Wang

Beilstein J. Nanotechnol. 2019, 10, 1943–1951, doi:10.3762/bjnano.10.190

• scattering region when RC is less than 30%. This is reasonable because a longer structure corresponds to a wider potential barrier in the scattering region due to the semiconducting BP section in the central region. Secondly, the variation of G is very small for each structure when RC is smaller than 15

Fabrication and characterization of Si_1−xGe_x nanocrystals in as-grown and annealed structures: a comparative study

• Muhammad Taha Sultan,
• Adrian Valentin Maraloiu,
• Ionel Stavarache,
• Jón Tómas Gudmundsson,
• Andrei Manolescu,
• Valentin Serban Teodorescu,
• Magdalena Lidia Ciurea and
• Halldór Gudfinnur Svavarsson

Beilstein J. Nanotechnol. 2019, 10, 1873–1882, doi:10.3762/bjnano.10.182

• SiGe layer, which in turn reduces the nucleation barrier. It can also be argued that since heterogeneous nucleation occurs at preferential sites (as in our case), small NCs in as-grown MLs or even the crystallites that are under strain [39][40][41][42] will further reduce the surface energy and

Engineered superparamagnetic iron oxide nanoparticles (SPIONs) for dual-modality imaging of intracranial glioblastoma via EGFRvIII targeting

• Xianping Liu,
• Chengjuan Du,
• Haichun Li,
• Ting Jiang,
• Zimiao Luo,
• Zhiqing Pang,
• Daoying Geng and
• Jun Zhang

Beilstein J. Nanotechnol. 2019, 10, 1860–1872, doi:10.3762/bjnano.10.181

• construct the nanoprobe. Both in vitro and in vivo MR and optical imaging demonstrated that the as-constructed nanoprobe was effective and sensitive for tumor targeting with desirable biosafety. Given its desirable properties such as a 100 nm diameter (capable of penetration of the blood–brain barrier) and

• through the blood–tumor barrier. Second, bimodal imaging combining magnetic resonance imaging and optical imaging provides a more accurate means for accurate diagnosis of glioblastoma. Third, the nanoprobe has good targeting to overexpressed EGFRvIII in glioblastoma and thus establishes a foundation for

Long-term entrapment and temperature-controlled-release of SF₆ gas in metal–organic frameworks (MOFs)

• Hana Bunzen,
• Andreas Kalytta-Mewes,
• Leo van Wüllen and
• Dirk Volkmer

Beilstein J. Nanotechnol. 2019, 10, 1851–1859, doi:10.3762/bjnano.10.180

• MOFs with ultranarrow pore apertures. Under elevated pressure and temperature, the gas molecules enter the pores, but they are not released immediately when normal conditions are re-established. This is due to the activation energy barrier for gas diffusion of the entrapped sorbate within the pores

Prestress-loading effect on the current–voltage characteristics of a piezoelectric p–n junction together with the corresponding mechanical tuning laws

• Wanli Yang,
• Shuaiqi Fan,
• Yuxing Liang and
• Yuantai Hu

Beilstein J. Nanotechnol. 2019, 10, 1833–1843, doi:10.3762/bjnano.10.178

• -bias voltage, a tensile (compressive) loading raises (reduces) the potential barrier of the space charge zone (SCZ), i.e., produces an equivalent reverse- (forward-) electric voltage on the SCZ. When a piezoelectric p–n junction is exposed to a reverse-bias voltage, the current density monotonically

• superposed upon step I [32] where (τn, τp) are the recombination lifetimes of electrons and holes, respectively. A forward-bias voltage lowers the potential barrier of the p–n junction such that majority carriers in the n- and p-zone, go across the SCZ to accumulate on the boundary at the other side as NEMC

• . The accumulation of minority carriers there will give rise to gradients of NEMC, which stimulates diffusion of NEMC departing from the two boundaries into the zones outside the SCZ and causes a positive current; a reverse-bias voltage increases the potential barrier such that minority carriers at the

Lipid nanostructures for antioxidant delivery: a comparative preformulation study

• Elisabetta Esposito,
• Maddalena Sguizzato,
• Markus Drechsler,
• Paolo Mariani,
• Federica Carducci,
• Claudio Nastruzzi,
• Giuseppe Valacchi and
• Rita Cortesi

Beilstein J. Nanotechnol. 2019, 10, 1789–1801, doi:10.3762/bjnano.10.174

• rejuvenating excipients have been developed. Nevertheless, these strategies offer merely a short-term improvement of skin barrier function. Thus, in this respect, there is an unmet need for an effective product that endows skin protection from pollutants from long-term exposure, as well as for antipollution

• and skin barrier improvement [17][18][19]. Vitamin A is defined as a group of lipophilic retinoids, including retinoic acid (RA), derived from food and stored in the liver. Due to its antioxidant action, RA plays a role in cancer chemoprevention and differentiation [20]. Particularly, RA has been

The impact of crystal size and temperature on the adsorption-induced flexibility of the Zr-based metal–organic framework DUT-98

• Simon Krause,
• Volodymyr Bon,
• Hongchu Du,
• Rafal E. Dunin-Borkowski,
• Ulrich Stoeck,
• Irena Senkovska and
• Stefan Kaskel

Beilstein J. Nanotechnol. 2019, 10, 1737–1744, doi:10.3762/bjnano.10.169

• , smaller crystal sizes seem to stabilize the presence of a metastable op phase by impacting the activation barrier, presumably due to the contribution of the surface energy and other factors. This observation was previously made for DUT-8 for which the guest-free metastable op phase was also found to be

Nanoporous smartPearls for dermal application – Identification of optimal silica types and a scalable production process as prerequisites for marketed products

• David Hespeler,
• Sanaa El Nomeiri,
• Jonas Kaltenbach and
• Rainer H. Müller

Beilstein J. Nanotechnol. 2019, 10, 1666–1678, doi:10.3762/bjnano.10.162

• ., rutin, hesperidin), which are presently en vogue in cosmetics for antipollution products (e.g., the “molecular barrier” against reactive oxygen species (ROS), infrared (IR) radiation and blue light from computers) [1][2]. For the delivery of such molecules, efficient delivery systems are the only

Unipolar magnetic field pulses as an advantageous tool for ultrafast operations in superconducting Josephson “atoms”

• Daria V. Popolitova,
• Nikolay V. Klenov,
• Igor I. Soloviev,
• Sergey V. Bakurskiy and
• Olga V. Tikhonova

Beilstein J. Nanotechnol. 2019, 10, 1548–1558, doi:10.3762/bjnano.10.152

• elements are EJos, EJos and αEJos, α > 0.5. The third junction can be replaced by a superconducting quantum interferometer, which allows one to adjust α using an external magnetic flux. So, we can apply magnetic fluxes ΦX and ΦZ in order to control the barrier height and potential asymmetry respectively

• setting the working point (see Figure 6). Here, the value ΦZ determines the potential asymmetry of the potential; the value ΦX determines parameter α and the size of the barrier between the minima of the potential presented in Figure 1. It can be seen that in a superconducting meta-atom we can really

• adjust the magnitude of the energy gap and even make it negligible. In addition, we can control the selection rules. There is a range of parameters in which, for example, the transition between the lowest energy levels is prohibited. For small sizes of the potential barrier between the minima (for

High-temperature resistive gas sensors based on ZnO/SiC nanocomposites

• Vadim B. Platonov,
• Marina N. Rumyantseva,
• Alexander S. Frolov,
• Alexey D. Yapryntsev and
• Alexander M. Gaskov

Beilstein J. Nanotechnol. 2019, 10, 1537–1547, doi:10.3762/bjnano.10.151

• material conductance, kB is the Boltzmann constant, the values of the activation energy Ea were calculated. For ZnO nanofibers, Ea = 0.40 ± 0.04 eV. This value lies within the error with the potential barrier at the grain boundaries eVs (the surface potential barrier energy between particles of

• ZnO surface, increasing the potential energy barrier and enhancing the response formed due to reactions (Equation 1 and Equation 2). The decrease in the sensor response observed for all the samples with an increase in the concentration of water vapor in the gas phase may be due to the competition of

Selective gas detection using Mn₃O₄/WO₃ composites as a sensing layer

• Yongjiao Sun,
• Zhichao Yu,
• Wenda Wang,
• Pengwei Li,
• Gang Li,
• Wendong Zhang,
• Lin Chen,
• Serge Zhuivkov and
• Jie Hu

Beilstein J. Nanotechnol. 2019, 10, 1423–1433, doi:10.3762/bjnano.10.140

• potential barrier, which facilitates the redox reaction on the surface and leads to a high response. However, when the working temperature exceeds a certain value, the gas desorption process surpasses adsorption, resulting in a decrease of the gas response [24]. An optimal working temperature is found to

Kelvin probe force microscopy of the nanoscale electrical surface potential barrier of metal/semiconductor interfaces in ambient atmosphere

• Petr Knotek,
• Tomáš Plecháček,
• Jan Smolík,
• Petr Kutálek,
• Filip Dvořák,
• Milan Vlček,
• Jiří Navrátil and
• Čestmír Drašar

Beilstein J. Nanotechnol. 2019, 10, 1401–1411, doi:10.3762/bjnano.10.138

• nanosheets through the reaction with the Bi2Se3. The Schottky barrier formed by the 1D and 2D nanoinclusions was characterized by means of atomic force microscopy (AFM). We used Kelvin probe force microscopy (KPFM) in ambient atmosphere at the nanoscale and compared the results to those of ultraviolet

• photoelectron spectroscopy (UPS) in UHV at the macroscale. The existence of the Schottky barrier was demonstrated at +120 meV for the Mo layer and −80 meV for the Au layer reflecting the formation of MoSe2 and Au/Bi2Se3 alloy, respectively. The results of both methods (KPFM and UPS) were in good agreement. We

• revealed that long-time exposure (tens of seconds) to the electrical field leads to deep oxidation and the formation of perturbations greater than 1 µm in height, which hinder the I–V measurements. Keywords: Kelvin probe atomic force microscope; nanoinclusion; Schottky barrier; thermoelectric materials

Nanoscale spatial mapping of mechanical properties through dynamic atomic force microscopy

• Zahra Abooalizadeh,
• Leszek Josef Sudak and
• Philip Egberts

Beilstein J. Nanotechnol. 2019, 10, 1332–1347, doi:10.3762/bjnano.10.132

• topography, environmental contamination, the Schwoebel–Ehrlich barrier, energy dissipation through viscoelastic energy losses, applied normal force, tip shape, and modulation frequency (both for CR and FMM modes). Each examination will show that the elastic modulus measured in the previous section is

• step edge resulting from the Schwoebel barrier [45][46] in the absence of contaminants with a rounded AFM tip as detected in the lateral forces acquired simultaneously [15]. More specifically, the elastic displacement of the step edge by the modulating normal force did not show any enhanced contrast in

• the acquired phase images in CR-AFM or FMM-AFM results, suggesting no additional viscoelastic energy losses from modulating the applied load during scanning at the step edge. Thus, the presence of the Schwoebel barrier did not significantly impact the mechanical property measurements. We further

On the relaxation time of interacting superparamagnetic nanoparticles and implications for magnetic fluid hyperthermia

• Andrei Kuncser,
• Nicusor Iacob and
• Victor E. Kuncser

Beilstein J. Nanotechnol. 2019, 10, 1280–1289, doi:10.3762/bjnano.10.127

• performed on ferrofluids of different volume fractions. The theoretical support for the specific evolution of the relaxation time constant and the anisotropy energy barrier versus the interparticle interactions in a perturbation approach of the simple Néel expression for the relaxation time is provided via

• only to increase the anisotropy energy barrier per nanoparticle but also to decrease the specific time constant in the simplest Néel–Brown expression of the relaxation time, which is usually considered only as a material dependent parameter. In this context, the threefold aim of this paper is: (i) to

• measurements and (iii) to provide theoretical support for the specific evolution of the relaxation time constant and the anisotropy energy barrier in the Néel expression as function of interparticle interaction through a suitable exploitation of static and time-dependent micromagnetic simulations. Results and

Molecular attachment to a microscope tip: inelastic tunneling, Kondo screening, and thermopower

• Rouzhaji Tuerhong,
• Mauro Boero and
• Jean-Pierre Bucher

Beilstein J. Nanotechnol. 2019, 10, 1243–1250, doi:10.3762/bjnano.10.124

• gaps where the tunneling barrier asymmetry at the STM–molecule junction becomes less critical. This asymmetry in the spectrum may suggest that two different vibration-assisted electron-transfer processes apparently compete, one involving a vibration-mediated Kondo effect, and the other, an inelastic

Imaging the surface potential at the steps on the rutile TiO₂(110) surface by Kelvin probe force microscopy

• Masato Miyazaki,
• Huan Fei Wen,
• Quanzhen Zhang,
• Yuuki Adachi,
• Jan Brndiar,
• Ivan Štich,
• Yan Jun Li and
• Yasuhiro Sugawara

Beilstein J. Nanotechnol. 2019, 10, 1228–1236, doi:10.3762/bjnano.10.122

• interpreting the change in work function at the steps by combining the upward dipole moment, in analogy to the Smoluchowski effect, and the local dipole moment of the surface atoms. This dipole moment is considered to lower the potential barrier for the adsorption of particular molecules, helping to suppress

Enhanced inhibition of influenza virus infection by peptide–noble-metal nanoparticle conjugates

• Zaid K. Alghrair,
• David G. Fernig and
• Bahram Ebrahimi

Beilstein J. Nanotechnol. 2019, 10, 1038–1047, doi:10.3762/bjnano.10.104

• the blood–brain barrier. Incubation of peripheral blood mononuclear cells with citrate and mixed-matrix gold nanoparticles demonstrates that the mixed-matrix ligand shell markedly reduces the reaction of the peripheral blood mononuclear cells to the nanoparticles [48]. Therefore, whilst it remains to

Serum type and concentration both affect the protein-corona composition of PLGA nanoparticles

• Katrin Partikel,
• Robin Korte,
• Dennis Mulac,
• Hans-Ulrich Humpf and
• Klaus Langer

Beilstein J. Nanotechnol. 2019, 10, 1002–1015, doi:10.3762/bjnano.10.101

• attracted to NPs composed of hydrophobic core materials [30][31] resulting in a prolonged circulation time in blood [18]. Moreover, covalent attachment of apolipoprotein A–I and apolipoprotein E to the NP surface enables drug transport across the blood–brain barrier [32]. Here, both proteins were identified

Effects of gold and PCL- or PLLA-coated silica nanoparticles on brain endothelial cells and the blood–brain barrier

• Aniela Bittner,
• Angélique D. Ducray,
• Hans Rudolf Widmer,
• Michael H. Stoffel and
• Meike Mevissen

Beilstein J. Nanotechnol. 2019, 10, 941–954, doi:10.3762/bjnano.10.95

• –brain barrier using rat brain capillary endothelial cells (rBCEC4). All types of nanoparticles were taken up time-dependently by the rBCEC4 cells, albeit to a different extent, causing a time- and concentration-dependent decrease in cell viability. Nanoparticle exposure did not change cell proliferation

• , differentiation, nor did it induce inflammation. rBCEC4 cells showed blood–brain barrier characteristics including tight junctions. None of the nanoparticles altered the expression of tight junctions or impaired the blood–brain barrier permeability. The findings suggest that effects of these nanoparticles on the

• metabolic state of cells have to be further characterized before use for medical purposes. Keywords: blood–brain barrier; laser tissue soldering; nanomedicine; nanoparticle uptake; rBCEC4 cells; Introduction Nanotechnology is commonly used in various fields, such as agriculture and pharmaceutical industry

Co-doped MnFe₂O₄ nanoparticles: magnetic anisotropy and interparticle interactions

• Bagher Aslibeiki,
• Parviz Kameli,
• Hadi Salamati,
• Giorgio Concas,
• Maria Salvador Fernandez,
• Alessandro Talone,
• Giuseppe Muscas and
• Davide Peddis

Beilstein J. Nanotechnol. 2019, 10, 856–865, doi:10.3762/bjnano.10.86

• ][49][50], being directly proportional to the energy barrier distribution, which produces a distribution of coercivities in the nanoparticle ensemble. As we can observe in Figure 5b, the average field of the SFD curve changes to higher values with respect to the Co content, reflecting the anisotropy

Capillary force-induced superlattice variation atop a nanometer-wide graphene flake and its moiré origin studied by STM

• Loji K. Thomas and
• Michael Reichling

Beilstein J. Nanotechnol. 2019, 10, 804–810, doi:10.3762/bjnano.10.80

• arm-chair direction can be found, which amounts to 172 eV. The interlayer binding energy in graphite is 44 meV/atom which is the van der Waals barrier that needs to be overcome for rotation to happen [45]. Theoretical studies showed that the energy barrier for rotation of graphene flakes on graphite

• is of the order of kBT [46][47][48], and for small angles, 25 meV/atom [47] will be a good approximation. Therefore the rotational barrier for the entire area of the flake is 28 keV. This energy is in kiloelectronvolts due to the very large number of atoms involved (see Table 1). The folding energy

• ca. 2.5 nm (a = 15 nm and r = 15/2π), respectively. This equation can also be written as Efold = k2πr·l/2r2 = πk·l/r, which yields around 126 eV for the folding energy barrier. Therefore, the total energy spent in rotation, tearing and folding of the flake adds up to about 28.3 keV. The tip–surface

An iridescent film of porous anodic aluminum oxide with alternatingly electrodeposited Cu and SiO₂ nanoparticles

• Menglei Chang,
• Huawen Hu,
• Haiyan Quan,
• Hongyang Wei,
• Zhangyi Xiong,
• Jiacong Lu,
• Pin Luo,
• Yaoheng Liang,
• Jianzhen Ou and
• Dongchu Chen

Beilstein J. Nanotechnol. 2019, 10, 735–745, doi:10.3762/bjnano.10.73

• potential to obtain the entire polarization curve. Since the potential of the electrode applied by the potentiostatic potential was sufficient to destroy the barrier layer of the sample to be tested, the potentiodynamic scanning must be performed after the electrical impedance test had been completed. The

The effect of translation on the binding energy for transition-metal porphyrines adsorbed on Ag(111) surface

• Luiza Buimaga-Iarinca and
• Cristian Morari

Beilstein J. Nanotechnol. 2019, 10, 706–717, doi:10.3762/bjnano.10.70

• -assembled structures at room temperature. An energy barrier around 0.03 eV would allow for free migration of the molecules on the surface at room temperature. We see that for all TMPP–Ag(111) systems the smallest barrier between two points is slightly smaller than 0.1 eV. This is the energy difference

• overcome a barrier of 0.1 eV. According to the data in Figure 2 the self-assembly will take place by successive jumps between bridge and hollow positions of the TM atom. Two comments should be made about this model: first, our previous discussion refers to the most probable scenario. Due to the large

• prefactor in the Boltzmann distribution law, even at a sub-monolayer coverage a large number of molecules are mobile on the surface. Also, following the same argumentation we can say that the direction of migration is not restricted from bridge to hollow positions. While the energy barrier along the bridge