The effect of surface charge on nonspecific uptake and cytotoxicity of CdSe/ZnS core/shell quantum dots

• Vladimir V. Breus,
• Anna Pietuch,
• Marco Tarantola,
• Thomas Basché and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 281–292, doi:10.3762/bjnano.6.26

• effect of surface charge was also observed for random and organized motions of internalized particles in the cellular interior, with both the diffusion coefficient and the velocity increasing in the following order: CA–QDs, DHLA–QDs, DPA–QDs. This result could be attributed to a decrease of the vesicle

• DPA–QDs show minimal aggregation due to the low pKa value (4.73) of the DHLA carboxylic group [32] and the colloidal stability over a wide pH range of the zwitterionic coating, respectively [33]. In order to clarify whether the CA–QDs and DHLA–QDs affect the cells differently due to their surface

• charge or the aggregation rate (which reduces the effective concentration of single QDs in solution), we studied an alternative, carboxylated, MPA-coated preparation, which is only partially deprotonated at pH 7.4. We found that independent of the type and concentration of CdSe/ZnS QDs, the MDCKII cells

Tailoring the ligand shell for the control of cellular uptake and optical properties of nanocrystals

• Johannes Ostermann,
• Christian Schmidtke,
• Christopher Wolter,
• Jan-Philip Merkl,
• Hauke Kloust and
• Horst Weller

Beilstein J. Nanotechnol. 2015, 6, 232–242, doi:10.3762/bjnano.6.22

• general (positively or negatively) show a much more efficient adsorption of these proteins needed for the recognition by macrophages [33][34]. Other cell types follow the endocytotic process, which can be receptor mediated or unspecific. For the uptake via endocytosis a positive surface charge has shown

• indicates, that the functional groups embedded on the outer part of the micelle do not interact significantly with the surface of the inorganic NP. In contrast, the surface charge was influenced by the end-group of the polymer as it was expected. This could be proven by zeta potential measurements in

Mechanical properties of MDCK II cells exposed to gold nanorods

• Anna Pietuch,
• Bastian Rouven Brückner,
• David Schneider,
• Marco Tarantola,
• Christina Rosman,
• Carsten Sönnichsen and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 223–231, doi:10.3762/bjnano.6.21

• dark-field microscopy together with transmission electron microscopy to quantify the uptake of gold nanoparticles into MDCK II cells as a function of shape, stabilizing agent, and surface charge [25]. We found that CTAB-coated particles are easily accumulated within cells, while PEG coatings inhibit

Caveolin-1 and CDC42 mediated endocytosis of silica-coated iron oxide nanoparticles in HeLa cells

• Nils Bohmer and
• Andreas Jordan

Beilstein J. Nanotechnol. 2015, 6, 167–176, doi:10.3762/bjnano.6.16

• and surface charge, were tested in HeLa cells as a model cell line. To elucidate, which molecular pathways are involved in their endocytosis, well-known endocytotic mechanisms [26][27][28] were inhibited by specific knockdown of key proteins via siRNA (Figure 1). Experimental Superparamagnetic iron

• ). These modifications resulted in different physicochemical properties referring to SPIONs surface charge and their size distribution under physiological conditions (Table 1). The primary particle size was determined by transmission electron microscopy (EM906, Zeiss). The zeta potential and the average

• . Fluorescent silica coated iron oxide nanoparticles (SCIONs) SCIONs were provided and characterized by the National Institute of Health (Maryland, USA). They were monodisperse at pH 7 and had a hydrodynamic diameter of 17 nm with a surface charge of 50 ± 5 mV. For detection in confocal fluorescence microscopy

The fate of a designed protein corona on nanoparticles in vitro and in vivo

• Denise Bargheer,
• Julius Nielsen,
• Gabriella Gébel,
• Markus Heine,
• Sunhild C. Salmen,
• Roland Stauber,
• Horst Weller,
• Joerg Heeren and
• Peter Nielsen

Beilstein J. Nanotechnol. 2015, 6, 36–46, doi:10.3762/bjnano.6.5

• radioactivity was determined in the fresh samples. Statistics To assess statistical significance the two-tailed, unpaired Student’s t-test was performed. P < 0.05 was considered as significant. Synthesis and characterization of polymer-coated SPIOs with different surface charge due to PEGylation with mono- or

Mammalian cell growth on gold nanoparticle-decorated substrates is influenced by the nanoparticle coating

• Christina Rosman,
• Sebastien Pierrat,
• Marco Tarantola,
• David Schneider,
• Eva Sunnick,
• Andreas Janshoff and
• Carsten Sönnichsen

Beilstein J. Nanotechnol. 2014, 5, 2479–2488, doi:10.3762/bjnano.5.257

• biocompatible polymer exhibiting one of two different end groups, resulting in a neutral or negative surface charge of the particle. Upon observation of cell growth for three days by live cell imaging using optical dark field microscopy, it was found that all particles supported cell adhesion while no directed

• was found that about 20% of apical applied CTAB nanorods enter the cell, whereas only a fraction of a percent of PEG nanorods (regardless of end group) were internalized. We attributed the differences in uptake to the surface charge of the particles favoring or disfavoring electrostatic interaction

• –PEG particles) or 75% COOH–PEG–SH and 25% CH3O–PEG–SH (COOH–PEG particles), respectively. The next day, excess PEG was removed by centrifugation. The success of the PEGylation was tested by gel electrophoresis, which also reveals the surface charge of the particles (Supporting Information of [20

Functionalized polystyrene nanoparticles as a platform for studying bio–nano interactions

• Cornelia Loos,
• Tatiana Syrovets,
• Anna Musyanovych,
• Volker Mailänder,
• Katharina Landfester,
• G. Ulrich Nienhaus and
• Thomas Simmet

Beilstein J. Nanotechnol. 2014, 5, 2403–2412, doi:10.3762/bjnano.5.250

• to size or surface properties of nanoparticles. By using polystyrene particles, it is possible to explore the effect of the size, the surface charge, and the hydrophobicity of the particles on cells. These studies show that, although, polystyrene has been claimed to be nontoxic, functionalized

Nanoparticle interactions with live cells: Quantitative fluorescence microscopy of nanoparticle size effects

• Li Shang,
• Karin Nienhaus,
• Xiue Jiang,
• Linxiao Yang,
• Katharina Landfester,
• Volker Mailänder,
• Thomas Simmet and
• G. Ulrich Nienhaus

Beilstein J. Nanotechnol. 2014, 5, 2388–2397, doi:10.3762/bjnano.5.248

• (RBCs) can internalize NPs only via passive transport [12]. The efficiency of NP internalization by a cell depends on cell-specific parameters such as cell type or cell cycle phase [13][14] and physicochemical properties of the NP [15]. Notably, NPs with positive surface charge are typically

• related to the different curvature of the adsorbed NPs experienced by the cell [19]. Apart from shape and surface charge, the NP size plays a crucial role in modulating the NP-cell interactions [20]. It affects the uptake efficiency and kinetics, the preference for certain internalization pathways as well

• , the zeta potentials of all NPs in PBS were also measured. As expected from the surface chemistry of the NPs, the NH2-modified (NPS) and the CTMA-adsorbed NPs carried a positive surface charge; all other preparations had a negative surface charge. Cellular uptake of small (diameter 3–10 nm) NPs Figure

Interaction of dermatologically relevant nanoparticles with skin cells and skin

• Annika Vogt,
• Fiorenza Rancan,
• Sebastian Ahlberg,
• Berouz Nazemi,
• Chun Sik Choe,
• Maxim E. Darvin,
• Sabrina Hadam,
• Ulrike Blume-Peytavi,
• Kateryna Loza,
• Jörg Diendorf,
• Matthias Epple,
• Christina Graf,
• Eckart Rühl,
• Martina C. Meinke and
• Jürgen Lademann

Beilstein J. Nanotechnol. 2014, 5, 2363–2373, doi:10.3762/bjnano.5.245

• Temperature Keratinocytes) and primary human keratinocytes showed an increased uptake of silica particles with positive surface charge under cell culture conditions, which was due to functionalization, e.g., through (3-aminopropyl)triethoxysilane (APS) (Figure 3) [3]. In the case of these silica particles

• ) or 75 nm (b,d) as well as negative (a,b) or positive (c,d) surface charge through funtionalization with (3-aminopropyl)triethoxysilane (APS) groups. Cells were incubated with particles (10 µg/mL, 2 h, 37 °C) and analyzed by means of flow cytometry (e,f) and confocal laser scanning microscopy (g

Inorganic Janus particles for biomedical applications

• Isabel Schick,
• Steffen Lorenz,
• Dominik Gehrig,
• Stefan Tenzer,
• Wiebke Storck,
• Karl Fischer,
• Dennis Strand,
• Frédéric Laquai and
• Wolfgang Tremel

Beilstein J. Nanotechnol. 2014, 5, 2346–2362, doi:10.3762/bjnano.5.244

• equivalent to that of pristine Atto495 and a second, but reduced PL lifetime as a consequence of the metal oxide-dye interaction. Additionally, aminosilanes, such as N-(6-aminohexyl)aminopropyltrimethoxysilane (AHAPS) or (3-aminopropyl)trimethoxysilane (APS), were applied to control the surface charge by

• peptides [112]. Consequently, this synthetic route allows precise control over nanoparticle composition, domain sizes, surface functionalization, and, also, surface charge. Biomedical applications When nanoparticles get in contact with body fluids, a variety of serum components binds to the surface of

• theranostics [113]. The analysis of the protein corona of nanoparticles shows that the binding profiles do not reflect the relative protein concentrations of the plasma. Recently, Tenzer et al. showed that there is no direct correlation of the surface charge and the isoelectric point of proteins enriched in

Nanoencapsulation of ultra-small superparamagnetic particles of iron oxide into human serum albumin nanoparticles

• Matthias G. Wacker,
• Mahmut Altinok,
• Stephan Urfels and
• Johann Bauer

Beilstein J. Nanotechnol. 2014, 5, 2259–2266, doi:10.3762/bjnano.5.235

• , particle diameter, size distribution, particle shape, and surface charge have been investigated. Characterization of magnetite core particles The magnetite structure was confirmed by the recorded powder X-ray diffraction (PXRD) patterns (Figure 1) exactly matching with the standard (ICDD card no. 19-629

• (TMAH). The positive surface charge of the particles enabled a strong interaction with the negatively charged protein matrix [13] provided by the HSA molecules. Formulation design and characterization of USPIO HSA hybrid particles by dynamic light scattering Nanoparticles were prepared by ethanolic

Effect of silver nanoparticles on human mesenchymal stem cell differentiation

• Christina Sengstock,
• Jörg Diendorf,
• Matthias Epple,
• Thomas A. Schildhauer and
• Manfred Köller

Beilstein J. Nanotechnol. 2014, 5, 2058–2069, doi:10.3762/bjnano.5.214

• comparing studies on the biological effects of nano-silver is the difference in the nature of the respective particle. In addition to the size, shape, or surface charge, the surface coating or functionalization used to stabilize the monodisperse nature is of critical importance. An important requirement is

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

• , independent of their surface charge. The differences in the thickness of the protein corona were rationalized in terms of the different orientations in which HSA adsorbs onto the NPs. The midpoints of the binding transition, which quantifies the affinity of HSA toward the NP, were observed to differ by almost

• binding with the large, triangular face, so that HSAsuc appears to bind preferentially in an upright position (Figure 4b, left). NP surface charge and HSA binding affinity Table 2 also contains affinity data, as quantified by the equilibrium binding coefficient, K′D, of native and modified HSA binding to

• proteins, HSAam and HSAsuc, have a larger fraction of positive and negative regions, respectively, than the native protein. A small, negatively charged metal NP is likely to find a small region with a positive surface charge, whereas the larger footprint of a QD will average over negative and positive

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

• particles (pKa ≈ 6–7) [19] which exhibit a negative surface charge in solution. It was, therefore, suggested that the stabilized sol consists of polyamine–silica nanoparticle superstructures resulting from a self-assembly process driven by attractive interactions between positively charged polyamines and

• 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

• should be supposed that a decreasing pH results in an increasingly positive charge. Moreover, the silica oligomers/nanoparticles in solution are supposed to exhibit a decreasingly negative surface charge at decreasing pH. If so, the repulsion among the increasingly positive PAH molecules would not be

Carbon-based smart nanomaterials in biomedicine and neuroengineering

• Antonina M. Monaco and
• Michele Giugliano

Beilstein J. Nanotechnol. 2014, 5, 1849–1863, doi:10.3762/bjnano.5.196

• substrates. This aspect has been investigated by Tu and colleagues [141], who cultured primary rat hippocampal neurons on carboxylated GO (GO-COOH; negative surface charge; control condition), the surface of which had been chemically modified by functionalisation with three functional groups: methoxy (-OCH3

• ; almost neutral surface charge), amino (NH2; positively charged surface) and poly-m-aminobenzene sulfonic acid (-NH2/-SO3H, PABS; zwitterionic). The viability of neurons after 7 DIV was estimated to be over 90% and, although no relevant differences in morphology were observed, neurons cultured on a

Electronic and electrochemical doping of graphene by surface adsorbates

• Hugo Pinto and
• Alexander Markevich

Beilstein J. Nanotechnol. 2014, 5, 1842–1848, doi:10.3762/bjnano.5.195

• concentration of charge carriers in graphene. Surface charge transfer can be mediated by two mechanisms, electronic and electrochemical doping. The electronic doping occurs by direct exchange of electrons between graphene and the adsorbates, either atoms or molecules. Electropositive elements that easily donate

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

• TEM, one is not able to detect agglomerates due to the fact that the arrangement of the particles is influenced by the preparation. Zeta potential (ZP) determination in water containing small amounts of salt (5 mM NaBr) yielded a value of −40 mV, which clearly shows the negative surface charge that is

• physiological salinity, zeta potential determinations based on electrophoretic mobility measurements should be treated with great care. As they are influenced by a multitude of factors, such as surface charge, salinity and by the interactions that are present in the colloid, the applied models to derive zeta

• particle characteristics to the biological responses that these particles induce. With the work presented here, a well-characterized system of SiO2-based nanomaterials is exhibited which allows for variations in surface properties (surface charge and polarity) as well as in the mechanism of colloidal

Nanocrystalline ceria coatings on solid oxide fuel cell anodes: the role of organic surfactant pretreatments on coating microstructures and sulfur tolerance

• Chieh-Chun Wu,
• Ling Tang and
• Mark R. De Guire

Beilstein J. Nanotechnol. 2014, 5, 1712–1724, doi:10.3762/bjnano.5.181

• –GDC composite). In previous studies of oxide film deposition on surfactant-treated surfaces, sulfonate surfaces strongly favored the formation of continuous films of ZrO2, TiO2, and SnO2 [26]. This outcome is attributed to the high negative surface charge density of well-packed sulfonate surfaces

In vitro and in vivo interactions of selected nanoparticles with rodent serum proteins and their consequences in biokinetics

• Wolfgang G. Kreyling,
• Stefanie Fertsch-Gapp,
• Martin Schäffler,
• Blair D. Johnston,
• Nadine Haberl,
• Christian Pfeiffer,
• Jörg Diendorf,
• Carsten Schleh,
• Stephanie Hirn,
• Manuela Semmler-Behnke,
• Matthias Epple and
• Wolfgang J. Parak

Beilstein J. Nanotechnol. 2014, 5, 1699–1711, doi:10.3762/bjnano.5.180

• abundance in serum. The determining factors with regard to the NP were: NP material, size, surface charge, surface curvature, surface ligand modifications and their stability during incubation. Concerning the proteins it was found that abundant proteins bind first but become replaced over time by proteins

Precise quantification of silica and ceria nanoparticle uptake revealed by 3D fluorescence microscopy

• Adriano A. Torrano and
• Christoph Bräuchle

Beilstein J. Nanotechnol. 2014, 5, 1616–1624, doi:10.3762/bjnano.5.173

• examples are particle characteristics such as size, morphology, chemical composition, surface charge and functionalization [1][2][3]. In addition, access to the number of intracellular particles is essential in studies aimed to compare the effect of similar particles on different cell types [4]. What all

Current state of laser synthesis of metal and alloy nanoparticles as ligand-free reference materials for nano-toxicological assays

• Christoph Rehbock,
• Jurij Jakobi,
• Lisa Gamrad,
• Selina van der Meer,
• Daniela Tiedemann,
• Ulrike Taylor,
• Wilfried Kues,
• Detlef Rath and
• Stephan Barcikowski

Beilstein J. Nanotechnol. 2014, 5, 1523–1541, doi:10.3762/bjnano.5.165

• pulse lengths but has not yet been sufficiently explained [43]. However, even though oxidation is meant to generate a positive surface charge, zeta potentials of laser-generated gold nanoparticles are all negative and titration with the positively charged ligand CTAB was used to confirm the presence of

• shown that aggregates may have significantly different toxicological effects than single particles [98][99]. Hence this chapter is meant to elucidate fundamental effects concerning nanoparticle stability, neglecting the specific influence of surface charge, which was fundamentally addressed in the

• previous paragraph and in other recent publications [45][100]. Furthermore details concerning surface charge–cell interactions, which are known to be involved in toxicity of nanoparticles are beyond the scope of this article and were described elsewhere [101][102]. Due to the absence of surface ligands

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

• adhesion are drawn. Parameters of the model substrates: Root mean square (rms) roughness, advancing (adv) and receding (rec) contact angles Θ of water, surface energy γ (values taken from [21]) and surface charge as revealed by streaming potential measurements at pH 7.3 [22]. Acknowledgements This work

In vitro interaction of colloidal nanoparticles with mammalian cells: What have we learned thus far?

• Moritz Nazarenus,
• Qian Zhang,
• Mahmoud G. Soliman,
• Pablo del Pino,
• Beatriz Pelaz,
• Susana Carregal-Romero,
• Joanna Rejman,
• Barbara Rothen-Rutishauser,
• Martin J. D. Clift,
• Reinhard Zellner,
• G. Ulrich Nienhaus,
• James B. Delehanty,
• Igor L. Medintz and
• Wolfgang J. Parak

Beilstein J. Nanotechnol. 2014, 5, 1477–1490, doi:10.3762/bjnano.5.161

• just stabilized by their surface charge (which can be directly on the inorganic surface) proteins will adsorb in serum-containing cell media and in this way can provide additional colloidal stability [129]. Therefore, there are no "naked" NPs in serum-containing cell culture media and inorganic NP

• ]. However, adsorption of proteins to the surface of NPs is not only driven by the basic physicochemical properties of the NP such as size, shape, surface charge, but also by other parameters such as the incubation temperature [139]. While model systems involving only one type of NPs and one type of protein

Protein-coated pH-responsive gold nanoparticles: Microwave-assisted synthesis and surface charge-dependent anticancer activity

• Dickson Joseph,
• Nisha Tyagi,
• Christian Geckeler and
• Kurt E.Geckeler

Beilstein J. Nanotechnol. 2014, 5, 1452–1462, doi:10.3762/bjnano.5.158

• for the capping of AuNPs, the resulting AuNPs were expected to behave differently under variable pH conditions [23]. Hence, pH-dependent zeta potential titration studies were performed to determine the surface charge of the AuNPs at different pH conditions. Cancer is one of the leading causes of early

• surface charge and that an excess of OH− ions are required for the net surface charge to be zero. In contrast, the OVA-AuNPs reach a zero net surface charge at pH 5.08, thus carrying predominantly negative charges on the surface of the OVA-AuNPs at their intrinsic pH. The IEPs of the remaining four AuNPs

• the highest IEP value of 10.58, which indicates that it carries a predominantly positive surface charge. The OVA-AuNPs had the lowest IEP value (5.08), indicating a predominant negative surface charge. The remaining four AuNPs had IEP values between 6 and 8.5. Correlating the IEP and the IC50 values

The cell-type specific uptake of polymer-coated or micelle-embedded QDs and SPIOs does not provoke an acute pro-inflammatory response in the liver

• Markus Heine,
• Alexander Bartelt,
• Oliver T. Bruns,
• Denise Bargheer,
• Artur Giemsa,
• Barbara Freund,
• Ludger Scheja,
• Christian Waurisch,
• Alexander Eychmüller,
• Rudolph Reimer,
• Horst Weller,
• Peter Nielsen and
• Joerg Heeren

Beilstein J. Nanotechnol. 2014, 5, 1432–1440, doi:10.3762/bjnano.5.155

• intravenous injection. As determined by DLS measurements, the sizes of QDs- or SPIOs-labelled lipid micelles are approximately 250 nm. After intravenous injection, lipid micelles are rapidly hydrolyzed to particles smaller than 100 nm in vivo [38]. Based on agarose gel electrophoresis, the surface charge of