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

• demonstrate that conjugation of FluPep to gold and silver nanoparticles enhances its antiviral potency; the antimicrobial activity of silver ions may enable the design of even more potent antimicrobial inhibitors, capable of targeting both influenza and bacterial co-infections. Keywords: antiviral peptides

Comparative biological effects of spherical noble metal nanoparticles (Rh, Pd, Ag, Pt, Au) with 4–8 nm diameter

• Alexander Rostek,
• Marina Breisch,
• Kevin Pappert,
• Kateryna Loza,
• Marc Heggen,
• Manfred Köller,
• Christina Sengstock and
• Matthias Epple

Beilstein J. Nanotechnol. 2018, 9, 2763–2774, doi:10.3762/bjnano.9.258

• oxidative release of silver ions [38][39][40][41][42][43], which may affect biological systems in different ways, for example, by disruption of the cell wall or by interaction with cellular enzymes [44]. However, it is often difficult to compare literature reports because typically only nanoparticles of one

• concentration from 25 to 50 µg mL−1 (Figure 7). These effects are well known for silver, silver chloride and silver ions [33][38][44][92]. Cell detachment was only observed at toxic concentrations of silver nanoparticles (25 to 50 µg mL−1), but not at subtoxic concentrations (2.5 to 10 µg mL−1). Thus, cell

• the toxicity of silver nanoparticles is due to the oxidative release of silver ions [38][39][40][43][67][94][95][96][97][98][99][100], we can tentatively assume that such a dissolution does not occur for the more noble metals, and that the nanoparticles themselves are not cytotoxic. Due to the more

SERS active Ag–SiO₂ nanoparticles obtained by laser ablation of silver in colloidal silica

• Cristina Gellini,
• Francesco Muniz-Miranda,
• Alfonso Pedone and
• Maurizio Muniz-Miranda

Beilstein J. Nanotechnol. 2018, 9, 2396–2404, doi:10.3762/bjnano.9.224

• occurs when silver ions are chemically reduced), as proposed in several papers [17][18][19][20][21][22][23]. Here, we have ablated a silver target in a colloidal silica solution by nanosecond pulsed laser ablation and have verified the presence of Ag nanoparticles by UV–visible absorption spectroscopy

The role of adatoms in chloride-activated colloidal silver nanoparticles for surface-enhanced Raman scattering enhancement

• Nicolae Leopold,
• Andrei Stefancu,
• Krisztian Herman,
• István Sz. Tódor,
• Stefania D. Iancu,
• Vlad Moisoiu and
• Loredana F. Leopold

Beilstein J. Nanotechnol. 2018, 9, 2236–2247, doi:10.3762/bjnano.9.208

• surface of silver chloride particles suspended in water. The photoconversion of silver salts to metallic silver particles is the basic principle of film photography: silver ions in silver halide particles are photoreduced by the transfer of electrons from halide ions [4][5]. Chloride anions are often

Facile chemical routes to mesoporous silver substrates for SERS analysis

• Elina A. Tastekova,
• Alexander Y. Polyakov,
• Anastasia E. Goldt,
• Alexander V. Sidorov,
• Alexandra A. Oshmyanskaya,
• Irina V. Sukhorukova,
• Dmitry V. Shtansky,
• Wolgang Grünert and
• Anastasia V. Grigorieva

Beilstein J. Nanotechnol. 2018, 9, 880–889, doi:10.3762/bjnano.9.82

• likely, this effect is related to recrystallization processes, which include removing silver ions from the lattice and its further deposition onto the exterior surface of the domains when reduced. Such a diffusion-limited reduction is the processing pathway towards a porous material with uniform pores

Colloidal solution of silver nanoparticles for label-free colorimetric sensing of ammonia in aqueous solutions

• Alessandro Buccolieri,
• Antonio Serra,
• Gabriele Giancane and
• Daniela Manno

Beilstein J. Nanotechnol. 2018, 9, 499–507, doi:10.3762/bjnano.9.48

• to control and stabilize the synthesis of nanoparticles by adding ammonia in colloidal solutions [18]. It is also known that ammonia reacts with silver ions and gives rise to [Ag(NH3)2]+ [19][20][21], a weak oxidant able to decrease the reduction rate [22]. When very stable complexes between silver

• the synthesis of silver nanoparticles improving oxidation of hydroxy groups in glucose, and giving rise to an accelerated reduction of silver in the fluid. The rationale of this behaviour is given by correlating the formation of nanoparticles to the content of silver ions in the solution. The

• concentration of silver ions is constant for all syntheses carried out in the present work. Initially, at low concentrations of ammonia, the oxidation of hydroxy groups facilitates the rate of nucleation of silver nanoparticles. Then a high rate of nucleation of silver nanoparticles was observed in the NH3

Vapor-based polymers: from films to nanostructures

• Meike Koenig and
• Joerg Lahann

Beilstein J. Nanotechnol. 2017, 8, 2219–2220, doi:10.3762/bjnano.8.221

• deposition, is used as a top layer above an electro-deposited silver coating, ensuring the prolonged release of antibacterial silver ions. Another advantage of vapor deposition techniques is the potential of synthesizing copolymers of chemically or functionally distinct monomers [12]. Alternatively, vapor

Bi-layer sandwich film for antibacterial catheters

• Gerhard Franz,
• Florian Schamberger,
• Hamideh Heidari Zare,
• Sara Felicitas Bröskamp and
• Dieter Jocham

Beilstein J. Nanotechnol. 2017, 8, 1982–2001, doi:10.3762/bjnano.8.199

• exterior side of the capillary neglects the fact that bacteria mainly ascend through the interior of the catheter. 2. Ag and its ions are well known as antibacterial reagent, but also to precipitate with Cl− ions to AgCl. Since urine is a 0.1 M solution of sodium chloride, silver ions could never work in

• easily precipitated by Cl− ions. The solubility product is 10−10 mol2/L2. Urine contains approximately 0.1 M of Cl−. Silver and silver ions can only be used because urine also contains urease and urea, which generate ammonia, NH3. Ammonia is responsible for a successful application of the antibacterial

• on the assumption that certain illnesses, such as necrosis are triggered by silver ions, but only for concentrations beyond a certain threshold value. These values are explicitly denoted as “estimated” and are given with an uncertainty of approximately one order of magnitude (averaged for all human

Optical response of heterogeneous polymer layers containing silver nanostructures

• Miriam Carlberg,
• Florent Pourcin,
• Olivier Margeat,
• Judikaël Le Rouzo,
• Gérard Berginc,
• Rose-Marie Sauvage,
• Jörg Ackermann and
• Ludovic Escoubas

Beilstein J. Nanotechnol. 2017, 8, 1065–1072, doi:10.3762/bjnano.8.108

• our structures, through AFM or TEM studies, may improve our optical models in the future. Experimental Synthesis of nanoparticles The NPs were synthesized by the reduction of silver ions by sodium borohydride at room temperature in water. The nanospheres were synthesized in a one-step method [17]. The

Structural properties and thermal stability of cobalt- and chromium-doped α-MnO₂ nanorods

• Romana Cerc Korošec,
• Polona Umek,
• Alexandre Gloter,
• Jana Padežnik Gomilšek and
• Peter Bukovec

Beilstein J. Nanotechnol. 2017, 8, 1032–1042, doi:10.3762/bjnano.8.104

• introduction of silver ions into the cryptomelane structure also lowered thermal stability due to a partial distortion of the regular channel-like structure [22]. The influence of doping the pristine material with different ions on its thermal stability is quite complex. When an ion of higher valence (3+, 2

Sandwich-like layer-by-layer assembly of gold nanoparticles with tunable SERS properties

• Zhicheng Liu,
• Lu Bai,
• Guizhe Zhao and
• Yaqing Liu

Beilstein J. Nanotechnol. 2016, 7, 1028–1032, doi:10.3762/bjnano.7.95

• alternating the adsorption of polyethyleneimine–silver ions and Au NPs onto substrates and the subsequent in situ reduction of the silver ions [17]. Compared with the parallel samples, the bimetallic LbL film showed improved SERS properties. Although a few examples of SERS substrates based on LbL strategy

Templated green synthesis of plasmonic silver nanoparticles in onion epidermal cells suitable for surface-enhanced Raman and hyper-Raman scattering

• Marta Espina Palanco,
• Klaus Bo Mogensen,
• Marina Gühlke,
• Zsuzsanna Heiner,
• Janina Kneipp and
• Katrin Kneipp

Beilstein J. Nanotechnol. 2016, 7, 834–840, doi:10.3762/bjnano.7.75

• the onion tissue. The luminescence pattern in Figure 1 shows that some silver ions are taken up into the protoplast during the osmotic imbalance when the hypertonic silver salt solution is added, and the small clusters must be stabilized there. In contrast, at the outer cell walls and in the

Antibacterial activity of silver nanoparticles obtained by pulsed laser ablation in pure water and in chloride solution

• Brunella Perito,
• Emilia Giorgetti,
• Paolo Marsili and
• Maurizio Muniz-Miranda

Beilstein J. Nanotechnol. 2016, 7, 465–473, doi:10.3762/bjnano.7.40

• microorganisms is not yet fully understood, it is generally believed that different mechanisms determine the antimicrobial activity of AgNPs based on both the release of silver ions and the nanoparticle characteristics [15][16]. Some of these proposed mechanisms include: (a) the direct contact between NPs and

• NP size. The UV–vis absorption spectra, instead, evidenced a larger content of oxidized silver on the surface of the ps-ablated nanoparticles. This results in the release of more silver ions, which is recognized to be quite important for the antimicrobial activity [15][16]. For the colloids obtained

Two step formation of metal aggregates by surface X-ray radiolysis under Langmuir monolayers: 2D followed by 3D growth

• Smita Mukherjee,
• Marie-Claude Fauré,
• Michel Goldmann and
• Philippe Fontaine

Beilstein J. Nanotechnol. 2015, 6, 2406–2411, doi:10.3762/bjnano.6.247

• place around the organic templates. We have previously applied this strategy to a spherical and a planar geometry. In the first case, we observed the formation of silver nanoshells upon irradiation of an aqueous solution of linoleic acid micelles that contained silver ions [6][7]. In the latter case, we

Ultrastructural changes in methicillin-resistant Staphylococcus aureus induced by positively charged silver nanoparticles

• Dulce G. Romero-Urbina,
• Humberto H. Lara,
• J. Jesús Velázquez-Salazar,
• M. Josefina Arellano-Jiménez,
• Eduardo Larios,
• Anand Srinivasan,
• Jose L. Lopez-Ribot and
• Miguel José Yacamán

Beilstein J. Nanotechnol. 2015, 6, 2396–2405, doi:10.3762/bjnano.6.246

• Abstract Silver nanoparticles offer a possible means of fighting antibacterial resistance. Most of their antibacterial properties are attributed to their silver ions. In the present work, we study the actions of positively charged silver nanoparticles against both methicillin-sensitive Staphylococcus

• species in a citrate-stabilized nanosilver colloidal solution was reported: neutral AgNPs (Ag0), silver ions (Ag+) and Ag+ adsorbed on Ag0 (Ag0/Ag+). Battharai et al. was able to show the presence of Ag0 by performing a TEM investigation. Additionally, the existence of Ag+ adsorbed on Ag0 was discovered

• plasmids has been studied by geneticists at a molecular level [46]. The continuous leaching of silver ions by AgNPs [42] creates a favorable antimicrobial environment. MSSA and MRSA were treated with a solution of AgNPs to study the ultrastructural changes and bactericidal and lytic effects that were

Synthesis, characterization and in vitro effects of 7 nm alloyed silver–gold nanoparticles

• Simon Ristig,
• Svitlana Chernousova,
• Wolfgang Meyer-Zaika and
• Matthias Epple

Beilstein J. Nanotechnol. 2015, 6, 1212–1220, doi:10.3762/bjnano.6.124

• reduces the amount of released silver ions. In a comparable toxicity study with laser-generated alloyed Ag/Au nanoparticles on cumulus-oocyte complexes and spermatozoa [38] and human gingival fibroblasts [39], a passivating effect of gold on silver was reported. In contrast to these studies, the toxicity

• and lower specific surface area, the pure silver nanoparticles should release silver ions at a lower rate. Furthermore, cells treated with nanoparticles that contain more gold than silver remained viable after 72 h. This increase in viability by addition of gold containing nanoparticles to the cells

• was also reported by Mahl et al. [30]. When investigations about cellular and bacterial toxicity are carried out, the purification of the nanoparticles is a crucial factor. As silver containing nanoparticles are often prone to release silver ions during storage that are more toxic than the

Protein corona – from molecular adsorption to physiological complexity

• Lennart Treuel,
• Dominic Docter,
• Michael Maskos and
• Roland H. Stauber

Beilstein J. Nanotechnol. 2015, 6, 857–873, doi:10.3762/bjnano.6.88

• silver NPs it was shown that their cytotoxicity is predominantly caused by the release of silver ions even when polymer coatings were applied [25][113][153]. The somewhat independent modes of action of the NP surface and the core need therefore to be considered in detail to assess the biological impact

Influence of gold, silver and gold–silver alloy nanoparticles on germ cell function and embryo development

• Ulrike Taylor,
• Daniela Tiedemann,
• Christoph Rehbock,
• Wilfried A. Kues,
• Stephan Barcikowski and
• Detlef Rath

Beilstein J. Nanotechnol. 2015, 6, 651–664, doi:10.3762/bjnano.6.66

• effect was caused by silver ions. However, it supports findings made on spermatogonial stem cells in vitro, which claimed a decrease in cell proliferation after AgNP exposure [40][41]. Observations concerning female reproductive organs are rather rare as most nanoparticle biodistribution studies have

• driven by oxidation and inflammation [77], it is unclear whether silver in its nanoparticulate form is responsible for the toxic effects, as some studies claim [78], or whether they are solely caused by silver ions dissolving in the course of oxidation of the metal [20]. In our study silver ions proved

• to be equally toxic than alloy particles containing 80% of silver and pure AgNP pointing out that at least their toxic potential is similar. More recent and so far unpublished data seems to further confirm the hypothesis, that silver nanoparticle toxicity is mainly derived from the silver ions. In a

Hematopoietic and mesenchymal stem cells: polymeric nanoparticle uptake and lineage differentiation

• Ivonne Brüstle,
• Thomas Simmet,
• Gerd Ulrich Nienhaus,
• Katharina Landfester and
• Volker Mailänder

Beilstein J. Nanotechnol. 2015, 6, 383–395, doi:10.3762/bjnano.6.38

• species (ROS) can lead to an increased release of IL-8. The observation of an increased IL-8 release has also been reported for silver ions/nanoparticles [33] with hMSCs. For hHSCs, no increase of IL-8 release was observed. Clearly, the effect on differentiation of hMSCs should be investigated separately

Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents

• Jes Ærøe Hyllested,
• Marta Espina Palanco,
• Nicolai Hagen,
• Klaus Bo Mogensen and
• Katrin Kneipp

Beilstein J. Nanotechnol. 2015, 6, 293–299, doi:10.3762/bjnano.6.27

• process such as laser ablation have the advantage of being “chemically clean” with no impurities on their surfaces introduced by the chemical preparation process. In the bottom up approach, nanoparticles are created from even smaller structures such as silver ions, which are the outcome of a chemical

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

• ROS were formed compared to AgNP which were produced and stored in an argon atmosphere. The oxygen in the ambient atmosphere is responsible for the formation of Ag+ ions by oxidation of the metallic silver nanoparticles. Silver ions are probably responsible for the induction of oxidative stress. In

• the argon atmosphere (in the absence of oxygen), the release of silver ions is strongly suppressed [46]. Taking the results of the uptake and cell viability into account, the data indicate that the silver ions formed during production and/or storage are mainly responsible for the induced oxidative

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

• through clathrin-dependent endocytosis and by macropinocytosis and that silver agglomerates were formed in the cytoplasm following the uptake of these nanoparticles [11]. There is a general consensus that dissolved silver ions are responsible for the majority of the biological effects on various cells and

• that the generation of reactive oxygen species is involved in the silver-induced cell response [9][12][13][14][15][16]. Previously, we have shown that silver ions are more toxic to hMSCs than Ag-NP (in terms of the absolute concentration of silver) [9][10]. This effect is approximately three times

• higher for silver ions than for Ag-NP; however, the biological effects induced by both nanoparticulate and ionic silver occurred in the same respective concentration ranges for eukaryotic cells and microorganisms [17][18][19]. We and others have studied the mechanisms underlying silver ion release from

PVP-coated, negatively charged silver nanoparticles: A multi-center study of their physicochemical characteristics, cell culture and in vivo experiments

• Sebastian Ahlberg,
• Alexandra Antonopulos,
• Jörg Diendorf,
• Ralf Dringen,
• Matthias Epple,
• Rebekka Flöck,
• Wolfgang Goedecke,
• Christina Graf,
• Nadine Haberl,
• Jens Helmlinger,
• Fabian Herzog,
• Frederike Heuer,
• Stephanie Hirn,
• Christian Johannes,
• Stefanie Kittler,
• Manfred Köller,
• Katrin Korn,
• Wolfgang G. Kreyling,
• Fritz Krombach,
• Jürgen Lademann,
• Kateryna Loza,
• Eva M. Luther,
• Marcelina Malissek,
• Martina C. Meinke,
• Daniel Nordmeyer,
• Anne Pailliart,
• Jörg Raabe,
• Fiorenza Rancan,
• Barbara Rothen-Rutishauser,
• Eckart Rühl,
• Carsten Schleh,
• Andreas Seibel,
• Christina Sengstock,
• Lennart Treuel,
• Annika Vogt,
• Katrin Weber and
• Reinhard Zellner

Beilstein J. Nanotechnol. 2014, 5, 1944–1965, doi:10.3762/bjnano.5.205

• types (alveolar epithelial cells, macrophages, and dendritic cells), adverse effects were also only found at high silver concentrations. The silver ions that are released from silver nanoparticles may be harmful to skin with disrupted barrier (e.g., wounds) and induce oxidative stress in skin cells

• undergo dissolution in water due to oxidation by dissolved oxygen [30][31][32][33]. This leads to the release of silver ions, which are the toxic agent towards cells and bacteria [20][29][33][34][35][36]. The dissolution of silver nanoparticles in water and other media has been studied by a number of

• assume that this is due to a strong binding of the thiol group to the silver metal surface, which prevents the dissolution by passivation. Glucose, which is often used in syntheses to reduce silver ions to silver metal, has a decelerating effect but leads to a similar fraction of silver being finally

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

• were both more pronounced in the presence of albumin. These findings may be attributed to the reduction of silver ions by surface bound citrate. The latter is frequently applied during the synthesis of silver nanoparticles [152][153], which in this case may reduce ion release and hence toxicity. In

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

• AuNPs. Conclusion For the first time, six different protein-coated AuNPs were prepared by using a single, rapid and green synthetic protocol that utilized microwave irradiation in an aqueous medium. The addition of silver ions to the reaction mixture enhanced the yield of AuNPs, which was confirmed by a