Exfoliation in a low boiling point solvent and electrochemical applications of MoO₃

• Matangi Sricharan,
• Bikesh Gupta,
• Sreejesh Moolayadukkam and
• H. S. S. Ramakrishna Matte

Beilstein J. Nanotechnol. 2020, 11, 662–670, doi:10.3762/bjnano.11.52

• the MoO3 layers were recorded using a 532 nm excitation laser. X-ray diffractograms (XRD; Rigaku Smart lab) of the bulk and exfoliated MoO3 were obtained using a Cu Kα (1.54 Å) X-ray source. The surface potential of MoO3 dispersions was determined by zeta potential measurements using a Malvern

• peaks at 485 and 733 cm−1 suggesting the presence of MoO3−x [13]. The Raman spectra clearly suggest that MoO3 nanosheets are chemically stable in 2-butanone even after exposure to sunlight. Zeta potential measurements were carried out to determine the charge on the surface of the nanosheets, which is

• critical for the stability of the dispersions. The high zeta potential of −33.5 mV (Figure 2f) affirms the stability of MoO3 dispersions in 2-butanone. Exfoliated two-dimensional materials are known to exhibit good electrochemical properties compared to the bulk materials [22][23]. The electrochemical

Silver-decorated gel-shell nanobeads: physicochemical characterization and evaluation of antibacterial properties

• Marta Bartel,
• Katarzyna Markowska,
• Marcin Strawski,
• Krystyna Wolska and
• Maciej Mazur

Beilstein J. Nanotechnol. 2020, 11, 620–630, doi:10.3762/bjnano.11.49

• anionic sulfonic groups) should be considerably diminished. To test this hypothesis, zeta potential measurements have been done. The analysis was performed in buffer solutions from pH 3 to pH 10 for the PSSAg beads, but also for PSS particles, PSS beads with incorporated silver ions and silver

• nanoparticles (non-incorporated in the polymer). The data is shown in Figure 6. One can see that for the PSS and the PSS with incorporated Ag+ ions the obtained results are very similar. At high pH values, the zeta potential values are ca. −30 mV, while they gradually increase with increasing pH value. This can

• be explained assuming that in both cases the negative charge of sulfonic groups is neutralized by sodium or silver cations. With decreasing pH values the sulfonate groups are increasingly protonated and the absolute value of the zeta potential decreases. The zeta potential of PSSAg beads exhibits

Identification of physicochemical properties that modulate nanoparticle aggregation in blood

• Ludovica Soddu,
• Duong N. Trinh,
• Eimear Dunne,
• Dermot Kenny,
• Giorgia Bernardini,
• Ida Kokalari,
• Arianna Marucco,
• Marco P. Monopoli and
• Ivana Fenoglio

Beilstein J. Nanotechnol. 2020, 11, 550–567, doi:10.3762/bjnano.11.44

• particles per frame, as suggested by the manufacturer’s recommendations. The measurement duration was set at 60 s. Zeta potential Zeta-potential measurements were performed based on the electrophoretic light scattering (ELS) technique, using a Zetasizer (Nano ZS Malvern Instruments, UK) instrument, as a

• nanoparticle samples comparing to the small ones. SEM analysis confirmed that all particles appear spherical with a uniform size, confirming the DLS analysis (Figure 1). The zeta potential of the samples was measured by electrophoretic light scattering (ELS) in the pH range from 2 to 9 (Figure 2a). As expected

• , both SNPs and CNPs exhibited a negative zeta potential across the whole pH range. It gradually increased with the increase of the pH of the suspension although it never reached positive values, indicating the presence of weakly acidic groups at the surface. In the case of CNPs, acidic carboxylic or

Multilayer capsules made of weak polyelectrolytes: a review on the preparation, functionalization and applications in drug delivery

• Varsha Sharma and
• Anandhakumar Sundaramurthy

Beilstein J. Nanotechnol. 2020, 11, 508–532, doi:10.3762/bjnano.11.41

• varying the size of the sacrificial template [10]. The shell thickness can also be altered by the number of layers and the preparation conditions, thus providing control over thickness and morphology. Notably, these capsules have better encapsulation efficiency (EE) and a stable zeta potential mainly due

Nanoparticles based on the zwitterionic pillar[5]arene and Ag⁺: synthesis, self-assembly and cytotoxicity in the human lung cancer cell line A549

• Dmitriy N. Shurpik,
• Denis A. Sevastyanov,
• Pavel V. Zelenikhin,
• Pavel L. Padnya,
• Vladimir G. Evtugyn,
• Yuriy N. Osin and
• Ivan I. Stoikov

Beilstein J. Nanotechnol. 2020, 11, 421–431, doi:10.3762/bjnano.11.33

• File 1, Table S1). The minimum polydispersity index (PDI) values (PDI = 0.041) were obtained for the macrocycle 3/AgNO3 = 1:10 ratio (c(3) = 10−4 M, c(AgNO3) = 10−3 M) with an average hydrodynamic diameter of 122 nm (Supporting Information File 1, Figure S14). The high value of the zeta potential of

• of 122 nm. The high values of the zeta potential of the system ζ (3/Ag+) = +31.8 mV additionally confirm the formation of a stabilized supramolecular system. The cytotoxic effect of pillar[5]arenes 3 and 4 on A549 cells in the MTT test was characterized. The compounds did not show a statistically

Synthesis and enhanced photocatalytic performance of 0D/2D CuO/tourmaline composite photocatalysts

• Changqiang Yu,
• Min Wen,
• Zhen Tong,
• Shuhua Li,
• Yanhong Yin,
• Xianbin Liu,
• Yesheng Li,
• Tongxiang Liang,
• Ziping Wu and
• Dionysios D. Dionysiou

Beilstein J. Nanotechnol. 2020, 11, 407–416, doi:10.3762/bjnano.11.31

• ) spectra were analyzed using an A300 spectrometer (Bruker, Germany) with DMPO as a free radical scavenger under visible light irradiation (λ = 420 nm) for 20 min. The surface properties were characterized via an ASAP 2020 instrument (Micromeritics, USA). The zeta potential was measured with a ZETASIZER

• , [photocatalyst]0 = 0.5 g L−1, volume = 100 mL, temperature = 25 °C. (b) Zeta potential of the CuO/tourmaline composite under various pH values. Five successive photocatalytic MB degradation (%) cycles over the CuO/tourmaline-4:1 composite. Experimental conditions: [MB]0 = 0.01 g L−1, [photocatalyst]0 = 0.5 g L−1

Brome mosaic virus-like particles as siRNA nanocarriers for biomedical purposes

• Alfredo Nuñez-Rivera,
• Pierrick G. J. Fournier,
• Danna L. Arellano,
• Ana G. Rodriguez-Hernandez,
• Rafael Vazquez-Duhalt and
• Ruben D. Cadena-Nava

Beilstein J. Nanotechnol. 2020, 11, 372–382, doi:10.3762/bjnano.11.28

• by flow cytometry (Figure 1B). The differences in the extent of cell internalization could be explained by the surface charge as revealed by zeta potential measurements. The flow cytometry analysis of cell internalization was also performed after trypsin treatment, which promotes detachment of the

• . Surprisingly, a remarkable difference was found. CCMV showed a high activation of macrophages, while BMV showed almost no immunogenic response (Figure 3C,D). There is 80% homology in the amino acids sequences of CCMV and BMV [21], however, they differ in their surface charge. The zeta potential at pH 7 was

• determined. Under these conditions, the zeta potential of CCMV is −9.27 ± 0.47 mV, more negative than that of BMV (−5.16 ± 0.40 mV). The surface charge of the capsid could be the reason why CCMV activates macrophage cells to a greater extent, because it is well known that at a higher anionic charge the

Poly(1-vinylimidazole) polyplexes as novel therapeutic gene carriers for lung cancer therapy

• Gayathri Kandasamy,
• Elena N. Danilovtseva,
• Vadim V. Annenkov and
• Uma Maheswari Krishnan

Beilstein J. Nanotechnol. 2020, 11, 354–369, doi:10.3762/bjnano.11.26

• 100, Perkin Elmer, USA). Dynamic light scattering (DLS) and zeta potential measurements: The hydrodynamic size of the PVI–siRNA polyplexes was measured on a Zetasizer Nano ZS (Malvern instruments, UK). Samples at different volume ratios containing a final siRNA concentration of 100 nM were used for

• the measurements. The measurements were made using a quartz microcell of 1 mL capacity and 3 mm path length. Clear disposable cells were employed for zeta potential measurements. All measurements were performed for each sample in triplicates 20 min after sample preparation at 25 °C. Electrophoresis

• nanoparticles in the size range of 80 to 120 nm is clearly discernible from the electron micrographs. The hydrodynamic diameter of the blank PVI nanoparticles measured using dynamic light scattering was found to be about 237 ± 34.6 nm. The zeta potential measured for the blank PVI nanoparticles in HEPES buffer

Understanding nanoparticle flow with a new in vitro experimental and computational approach using hydrogel channels

• Armel Boutchuen,
• Dell Zimmerman,
• Abdollah Arabshahi,
• John Melnyczuk and
• Soubantika Palchoudhury

Beilstein J. Nanotechnol. 2020, 11, 296–309, doi:10.3762/bjnano.11.22

• obtain varying size and surface charge of the iron oxide NPs and to render the NPs biocompatible. Figure 5a shows a representative schematic of the iron oxide NPs synthesized. The hydrodynamic sizes and zeta potential values of the different iron oxide NPs were investigated in detail using a Litesizer

• (PDI: 0.17) and 140 nm (PDI: 0.12), respectively. The iron oxide NP formulations showed similar surface charges (Figure 5c). The low absolute values of zeta potential of the NPs suggested positively charged surfaces stabilized via steric hindrances from the polymer coating. The experimental flow

• . Characterization of iron oxide nanoparticles A Litesizer 500 (Anton Paar) particle analyzer equipped with zeta potential capability was used to measure the hydrodynamic size, stability, and surface charge of aqueous dispersions of iron oxide NPs at pH 7 at room temperature (Figure S4, Supporting Information File 1

Phase inversion-based nanoemulsions of medium chain triglyceride as potential drug delivery system for parenteral applications

• Eike Folker Busmann,
• Dailén García Martínez,
• Henrike Lucas and
• Karsten Mäder

Beilstein J. Nanotechnol. 2020, 11, 213–224, doi:10.3762/bjnano.11.16

• concentration of the surfactant Kolliphor HS 15 and hence the increase of the ratio of Kolliphor HS 15 to MCT resulted in a prompt decrease of the particle diameter. The constant limit is reached at ratios above three. The zeta potential of all nanoemulsions shown in Figure 4c was slightly negative between −1.6

• . Particle size and zeta potential measurement Particle diameters and zeta potentials were determined with the Malvern Instruments Zetasizer Nano ZS. To determine the particle diameters, the samples were diluted 1:100 in water and three measurements of 15 runs were conducted at 25 °C in the backscattering

• mode. The zeta potential was determined in triplicate with samples diluted 1:10 in 0.1× PBS with pH 7.4 at 25 °C with 10 to 50 runs per measurement. Investigation of the stability The samples were stored at 5 ± 3 °C, room temperature and at 40 ± 2 °C according to the storage conditions of the ICH

Long-term stability and scale-up of noncovalently bound gold nanoparticle-siRNA suspensions

• Anna V. Epanchintseva,
• Julia E. Poletaeva,
• Dmitrii V. Pyshnyi,
• Elena I. Ryabchikova and
• Inna A. Pyshnaya

Beilstein J. Nanotechnol. 2019, 10, 2568–2578, doi:10.3762/bjnano.10.248

• ±0.025 and 0.304 ± 0.010, respectively, thus indicating the homogeneity of the suspensions [23]. The main part (≈90% of the average value of the zeta potential) of the AuNP-siRNA particles in samples ×1 and ×10 had a charge of −38.85 ± 2.66 mV and −49.42 ± 2.07 mV, respectively (the main peaks in Figure

•  1C,D). The seed AuNP-siRNA (citrate) AuNPs had a zeta potential value of −33.6 ± 2.0 mV, indicating that attachment of siRNA influenced this value. The analysis of the zeta potential values of samples ×1 and ×10 revealed changes in the ratio between particles with different surface charge; this is

• clearly illustrated by the shape of the curves (Figure 1C,D; Supporting Information File 1, Table S1). At the same time, there were the particles with a charge value of −78.84 ± 10.85 mV (sample ×1) and −20.59 ± 8.04 mV (sample ×10), which was 9–11% of the average value of zeta potential. The average zeta

Bombesin receptor-targeted liposomes for enhanced delivery to lung cancer cells

• Mohammad J. Akbar,
• Pâmela C. Lukasewicz Ferreira,
• Melania Giorgetti,
• Leanne Stokes and
• Christopher J. Morris

Beilstein J. Nanotechnol. 2019, 10, 2553–2562, doi:10.3762/bjnano.10.246

• formulations were prepared using the thin-film technique to yield small and monodisperse vesicles as judged by dynamic light scattering (DLS) analysis (Table 1). The colloidal properties of both liposomal formulations were highly similar in terms of size, polydispersity and zeta potential and consistent with

• those reported for other pegylated liposomes by others [27]. The vesicles were colloidally stable in PBS over 72 h at temperatures of 4, 25 and 37 °C with no significant changes in size, PDI or zeta potential observed (Figure 3a,b). It was noted that the diameter of both liposome formulations was larger

• and 50 nm pore sizes to produce a narrow size distribution of LUVs. Characterization of liposomal formulations Liposomes were characterized for size and zeta potential using Zetasizer Nano ZS. For size measurements the liposomal suspension was diluted 1:10 with PBS. For zeta potential measurements

pH-Controlled fluorescence switching in water-dispersed polymer brushes grafted to modified boron nitride nanotubes for cellular imaging

• Saban Kalay,
• Yurij Stetsyshyn,
• Volodymyr Donchak,
• Khrystyna Harhay,
• Ostap Lishchynskyi,
• Halyna Ohar,
• Yuriy Panchenko,
• Stanislav Voronov and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2019, 10, 2428–2439, doi:10.3762/bjnano.10.233

• 9600 nm/min scan rate. The excitation and emission wavelength and the maximum fluorescence intensity of each peak were recorded. The concentration of BNNTs was 1 mg/mL. The pH of the suspension was adjusted by adding HCl or NaOH. Dynamic light scattering (DLS) The size distribution and zeta potential

• the nanomaterial were assumed to be 2.0 and 1.500, respectively. All size and zeta potential measurements were carried out in triplicate. All data were analyzed by using Malvern Instrument DST 5.00 software. 1 mg of sample was suspended in 1 mL of distilled water and sonicated for 2–10 min. After the

• -distribution profile (Figure 6) and zeta potential of BNNTs and P(AA-co-FA)-functionalized BNNTs in water were also studied. P(AA-co-FA)-functionalized BNNTs demonstrate a smaller Z-average diameter than the native BNNTs. The zeta potentials of BNNTs and P(AA-co-FA)-functionalized BNNTs are −19.4 and −14.3 mV

Coating of upconversion nanoparticles with silica nanoshells of 5–250 nm thickness

• Cynthia Kembuan,
• Maysoon Saleh,
• Bastian Rühle,
• Ute Resch-Genger and
• Christina Graf

Beilstein J. Nanotechnol. 2019, 10, 2410–2421, doi:10.3762/bjnano.10.231

• remain constant. Hence, the number of micelles stays constant, and their size is increased to accommodate the growing core–shell particles. Consequently, the formation of core-free silica particles is suppressed. When the negative zeta potential of the particles, which continuously decreased during the

• shell followed by the Stöber-like regrowth. Similar findings were also obtained for larger UCNP. It turned out in several preliminary experiments conducted by the same procedure that the zeta potential of the particles after the initial silica growth in the reverse microemulsion was always only around

• significantly alter their zeta potential. For this reason, further silica shell growth was performed in a reverse microemulsion. For this procedure, initially, the concept for growing larger silica shells on oleate-coated iron oxide NPs introduced by Ding et al. was adapted for the UCNPs [36] and used for a

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

• − showing a high affinity for the silver surface. The colloidal nanoparticles used here are surrounded by citrate anions in an electrostatic interaction with the silver surface, which confer the nanoparticles a negative zeta potential and thus electrostatically stabilize the AgNPs and prevent aggregation

Incorporation of doxorubicin in different polymer nanoparticles and their anticancer activity

• Sebastian Pieper,
• Hannah Onafuye,
• Dennis Mulac,
• Jindrich Cinatl Jr.,
• Mark N. Wass,
• Martin Michaelis and
• Klaus Langer

Beilstein J. Nanotechnol. 2019, 10, 2062–2072, doi:10.3762/bjnano.10.201

• comparatively simple preparation methods. The resulting nanoparticles were compared by particle diameter, polydispersity index, zeta potential, drug load, and drug release behaviour. Preliminary results on the preparation of doxorubicin-loaded PLGA nanoparticles have been previously published [34]. Selected

• had no influence on the nanoparticle characteristics such as particle diameter, PDI, and zeta potential (Table 2). However, loading efficiency and drug load increased. The drug load raised from 6.7 ± 0.3 µg doxorubicin/mg nanoparticle (44.8 ± 5.8% loading efficiency) without pH adjustment to 7.9 ± 0.8

• particle size, size distribution and zeta potential Average particle size and the polydispersity were measured by photon correlation spectroscopy (PCS) using a Malvern zetasizer nano (Malvern Instruments, Herrenberg, Germany). The resulting particle suspensions were diluted 1:100 with purified water and

Gold-coated plant virus as computed tomography imaging contrast agent

• Alaa A. A. Aljabali,
• Mazhar S. Al Zoubi,
• Khalid M. Al-Batanyeh,
• Ali Al-Radaideh,
• Mohammad A. Obeid,
• Abeer Al Sharabi,
• Walhan Alshaer,
• Bayan AbuFares,
• Tasnim Al-Zanati,
• Murtaza M. Tambuwala,
• Naveed Akbar and
• David J. Evans

Beilstein J. Nanotechnol. 2019, 10, 1983–1993, doi:10.3762/bjnano.10.195

• correlogram generated by the DLS instruments, that measures the time at which the correlation starts to significantly decay, gave a slope of 85.3° consistent with a monodisperse distribution. The steeper the line (closer to 90°) the more monodisperse the particles are. The zeta potential cannot be measured

• directly, rather it is deduced from the electrophoretic mobility of the charged NPs under an applied electric field. The electrophoretic mobility toward the positive or the negative electrode determines the zeta potential values as negative or positive. The zeta potential values for Au-CPMV particles of

• different suspensions are summarized in Table 1. The zeta potential is consistent, in each case, with the formation of a similar layer deposited on the surface of the Au-CPMV particles [34]. The zeta potential values of unfunctionalized Au-CPMV agrees with previously reported values [35] ranging between

Synthesis and potent cytotoxic activity of a novel diosgenin derivative and its phytosomes against lung cancer cells

• Liang Xu,
• Dekang Xu,
• Ziying Li,
• Yu Gao and
• Haijun Chen

Beilstein J. Nanotechnol. 2019, 10, 1933–1942, doi:10.3762/bjnano.10.189

• sterol structure similarly to cholesterol, P2 phytosomes (P2Ps) were prepared to further improve the water solubility of P2. The P2Ps exhibited a particle size of 53.6 ± 0.3 nm with oval shape and a zeta potential of −4.0 ± 0.7 mV. P2Ps could inhibit the proliferation of lung cancer cells more

• , Di phytosomes (DiP) and P2 phytosomes (P2P) were prepared by a thin-film rehydration method (Figure 3A). Blank lipid nanoparticles without drugs (P) were also prepared with the same process. Particle size and zeta potential of the phytosomes were measured by dynamic light scattering (DLS). The

• of liposomal membranes [34]. The existence of cholesterol analogues Di and P2 in phytosomes could improve the structural stability of phytosomes. The zeta potential values of DiP and P2P were −6.4 and −4.0 mV, respectively. Because the negatively charged particles interact weakly with negatively

Preservation of rutin nanosuspensions without the use of preservatives

• Pascal L. Stahr and
• Cornelia M. Keck

Beilstein J. Nanotechnol. 2019, 10, 1902–1913, doi:10.3762/bjnano.10.185

• changes the charge of the particles (zeta potential) and forces agglomeration of the nanocrystals. To avoid instabilities of nanosuspensions only very hydrophilic and non-charged preservatives, which will not interact with the nanocrystals, should be used. Due to the above-mentioned reasons, only a few

• stability than the Plantacare-stabilized formulations. Upon the addition of the preservatives only very minor changes in size were observed for both formulations (Table 1) and for the Plantacare-stabilized formulation even a slight deagglomeration was determined (Table 2). Also the zeta potential values did

• should become visible in the zeta potential values. However, this was not the case in this study (Figure 8). Therefore, the observed destabilization at elevated temperatures of the non-preserved nanosuspensions might be more related to Ostwald ripening. The assumption is also underlined by the fact that

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

• ), followed by negative staining with 2% phosphotungstic acid. The mean hydrodynamic diameter and zeta potential of the nanoprobes were measured with a Malvern Zetasizer Nano ZS (Malvern, UK) instrument. The quantitative measurement of the Fe content in PNPs was conducted by inductively coupled plasma

• accumulate in tumor tissue under the influence of enhanced permeability and retention (EPR) as previously discussed in the literature [43][44]. The zeta potential of the NPs and PNPs was found to be around −35.6 mV and −26.2 mV, respectively. The less negative value of the PNP zeta potential as compared to

• the NP zeta potential confirmed the successful conjugation of the positive-valued targeting peptide PEPHC1 (Figure 1d). High-performance liquid chromatography (HPLC) determination (results not shown) further supported the successful conjugation of PEPHC1 where the conjugation efficiency of the PEPHC1

Nanoarchitectonics meets cell surface engineering: shape recognition of human cells by halloysite-doped silica cell imprints

• Elvira Rozhina,
• Ilnur Ishmukhametov,
• Svetlana Batasheva,
• Farida Akhatova and
• Rawil Fakhrullin

Beilstein J. Nanotechnol. 2019, 10, 1818–1825, doi:10.3762/bjnano.10.176

• media supplemented with yeast cells. HeLa cells (having originally a negative zeta potential of ca. −10 mV) were first coated with a single layer of poly(acrylamide-co-diallyldimethylammonium chloride (P(AAm-co-DADMAC)) to reverse the surface charge of HeLa cells (the zeta potential after P(AAm-co

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

• biothiols (GSH and CYS) bind to the NP surfaces in their oxidized form, which supports some earlier reports [51][69]. A detailed characterization of the prepared NPs dispersed in ultrapure water (UPW) revealed a negative surface charge. The observed zeta-potential values (Table 1) were indicative of a high

• NP stability, as the NPs are generally considered electrostatically stabilized when the absolute values of the zeta potential exceed 30 mV [70]. The size distribution of all NPs was bimodal and the AgNPs were generally smaller than the AuNPs (Table 1). TEM experiments showed a spherical shape for all

• measuring the electrophoretic mobility, which was converted to zeta potential (ζ) values using the Henry equation with the Smoluchowski approximation. The measurements were repeated five times. The DLS and ELS data processing was performed using Zetasizer software 6.32 (Malvern Instruments, Malvern, UK

Doxorubicin-loaded human serum albumin nanoparticles overcome transporter-mediated drug resistance in drug-adapted cancer cells

• Hannah Onafuye,
• Sebastian Pieper,
• Dennis Mulac,
• Jindrich Cinatl Jr.,
• Mark N. Wass,
• Klaus Langer and
• Martin Michaelis

Beilstein J. Nanotechnol. 2019, 10, 1707–1715, doi:10.3762/bjnano.10.166

• stabilised by a 100% cross-linking degree (Figure 1). For these nanoparticles a zeta potential of −12.5 ± 1.8 mV (n = 6) was detected, indicating only a moderate stabilisation by electrostatic repulsion. While HSA (40%), HSA (100%), and HSA (200%) nanoparticles displayed similar drug loads between 152 and

• suspensions were diluted 1:100 with purified water and measured at a temperature of 22 °C using a backscattering angle of 173°. The zeta potential was measured in the same instrument by laser Doppler microelectrophoresis to provide information about the surface charge of the nanoparticles. Thus, the

Effects of surface charge and boundary slip on time-periodic pressure-driven flow and electrokinetic energy conversion in a nanotube

• Mandula Buren,
• Yongjun Jian,
• Yingchun Zhao,
• Long Chang and
• Quansheng Liu

Beilstein J. Nanotechnol. 2019, 10, 1628–1635, doi:10.3762/bjnano.10.158

• concentration and z is the valence of ions. Taking the Debye–Hückel approximation for low zeta potential, i.e., sinh(ezφ/(kBT)) ≈ ezφ/(kBT), and utilizing Equation 3 and Equation 4 we obtain the linearized Poisson–Boltzmann equation The electric potential distribution φ satisfies where ρe = −εκ2φ is used, ζ is

• the zeta potential, and κ = [εkBT/(2z2e2n0)]−1/2 is the Debye–Hückel parameter and represents the inverse of the characteristic EDL thickness. A unidirectional flow along the z-direction is generated by a time-periodic pressure gradient cos(ωt)dp0/dz independent of position, where ω is the frequency

• governing equations and their boundary conditions: where λ = εζ2/(µD), B2 = iRe, and Re = ωa2ρ/μ is the nondimensional frequency. Using numerical methods, Erickson and Li [32] verified that the linearized Equation 17 and Equation 19 are also valid for large zeta potential values up to 100 mV. Analytical

Janus-micromotor-based on–off luminescence sensor for active TNT detection

• Ye Yuan,
• Changyong Gao,
• Daolin Wang,
• Chang Zhou,
• Baohua Zhu and
• Qiang He

Beilstein J. Nanotechnol. 2019, 10, 1324–1331, doi:10.3762/bjnano.10.131

• surface charge of the UCNPs before and after modification was measured. As shown in Figure 1d, the zeta potential changed from −22.08 to 17.3 mV, indicating the successful surface amine group functionalization. Moreover, the fluorescence emission spectrum shows that the surface functionalization did not

• spectra, (d) zeta potential and (e) fluorescence emission spectrum of UNCPs with different surface functional groups. TEM images of UCNP-modified capsule (f) and Janus UCNP capsule motor (g). (h) SEM image of the Janus UCNP capsule motor. (i) Fluorescence microscope image of the Janus UCNP capsule motors