Silica micro/nanospheres for theranostics: from bimodal MRI and fluorescent imaging probes to cancer therapy

• Shanka Walia and
• Amitabha Acharya

Beilstein J. Nanotechnol. 2015, 6, 546–558, doi:10.3762/bjnano.6.57

• retains its tetragonal structure even after silica encapsulation. Further FTIR studies were carried out to characterize the NPs. The absorption peaks at 800, 965, 1110 and 830 cm−1 were attributed to Si–OH bending vibrations, Si–OH, Si–O–Si stretching vibrations and V–O vibrations of YVO4, respectively

• , and UV–vis and fluorescence spectroscopy studies. The TEM micrographs and EDX studies clearly indicate the encapsulation of both Fe2O3/CdSe(ZnS) NPs inside the silica shell. In cryo-TEM studies CdSe(ZnS)/SiO2/PNIPAAm NPs displayed a fuzzy corona-like structure. All these studies lead to the conclusion

• and QDs that were then encapsulated inside silica by using cyclohexane and TEOS. The TEM micrographs clearly indicated the incorporation of both types of NPs inside the silica shell. Such encapsulation studies were carried out at different time intervals but only after 48 h the spherical shaped silica

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

• ]. Various functionalization strategies have been employed in order to increase the stability of the surface ligand shell and to reduce the cytotoxicity of QDs, such as the use of cross-linked polymer coatings [10][12][13] or encapsulation in a silica shell [14][15][16]. These approaches, however, also

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

• application are addressed. It is shown how to overcome the different issues by the use of a polymeric encapsulation system, based on an amphiphilic polyisoprene-block-poly(ethylene glycol) diblock copolymer. On the basis of this simple molecule, the development of a versatile and powerful phase transfer

• solvents, which are selective for only one of the blocks [7]. The formation of polymeric vesicles (polymerosomes) and spherical micelles is an interesting tool for the encapsulation of hydrophobic nanoparticles and since the critical micelle concentration (CMC) is comparatively low [8][9], a high stability

• termination reactions, which gives the opportunity to easily functionalize the polymer chains using specific terminating reagents [11][12]. In this short review we summarize our experiences with amphiphilic diblock copolymers for the encapsulation of inorganic nanoparticles for their use in biomedical

The distribution and degradation of radiolabeled superparamagnetic iron oxide nanoparticles and quantum dots in mice

• Denise Bargheer,
• Artur Giemsa,
• Barbara Freund,
• Markus Heine,
• Christian Waurisch,
• Gordon M. Stachowski,
• Stephen G. Hickey,
• Alexander Eychmüller,
• Jörg Heeren and
• Peter Nielsen

Beilstein J. Nanotechnol. 2015, 6, 111–123, doi:10.3762/bjnano.6.11

• at 72 h and 96 h. The amount of radioactivity that was released into the buffer after the first 24 h could be attributed to free 65Zn ions from the encapsulation technique. Further loss of the label during the course of time could indicate a small but continuous bleeding of the radioactive isotope

• oleic acid and 22 mL of 1-octadecene was held at 320 °C under nitrogen for about 80 min. The 11 nm core diameter particles showed a narrow size distribution (less than 10% standard deviation) as confirmed by transmission electron microscopy (TEM). Encapsulation with the PMAOD solution was achieved using

• incubation of monodisperse, oleic acid-stabilized core particles (CdSe/CdS/ZnS-quantum dots, 5.5 or 7 nm; SPIOs, 11 nm) in chloroform with water-free 51CrCl3 or 65ZnCl2. The hydrophobic cores were then transferred into aqueous medium by encapsulation with a well-characterized amphiphilic polymer, poly[maleic

Synthesis of boron nitride nanotubes and their applications

• Saban Kalay,
• Zehra Yilmaz,
• Ozlem Sen,
• Melis Emanet,
• Emine Kazanc and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2015, 6, 84–102, doi:10.3762/bjnano.6.9

• and optical band gap properties was evaluated [91]. Two intense blue emission peaks at ~480 nm and ~365 nm were observed upon encapsulation of BNNTs with Ni. The time-resolved photoluminescence spectroscopy (TRPL) provided a photoluminescence spectrum with a bi-exponential decay of 280 ps. It was

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

• used as model hydrophobic monodisperse iron oxide nanoparticles, obtained from a high-temperature synthesis, which were transferred into aqueous medium by encapsulation with the well-characterized amphiphilic polymer, poly(maleic anhydride-alt-1-octadecene) [24][25]. These particles are negatively

• mmol) and 22 mL 1-octadecene was heated to 320 °C under nitrogen and kept at this temperature for about 80 min. The 11 nm core sized particles showed a narrow size distribution (less than 10% standard deviation) as confirmed by transmission electron microscopy (TEM). Encapsulation with poly(maleic acid

Intake of silica nanoparticles by giant lipid vesicles: influence of particle size and thermodynamic membrane state

• Florian G. Strobl,
• Florian Seitz,
• Christoph Westerhausen,
• Armin Reller,
• Adriano A. Torrano,
• Christoph Bräuchle,
• Achim Wixforth and
• Matthias F. Schneider

Beilstein J. Nanotechnol. 2014, 5, 2468–2478, doi:10.3762/bjnano.5.256

• proteins (e.g., clathrin coats) or the induction of membrane asymmetry [14][15]. The three main steps of such an uptake are depicted in Figure 1: adhesion to the membrane, bending of the membrane until the full encapsulation of the cargo and detachment of a vesicle from the membrane by a fission process

Synthesis of radioactively labelled CdSe/CdS/ZnS quantum dots for in vivo experiments

• Gordon M. Stachowski,
• Christoph Bauer,
• Christian Waurisch,
• Denise Bargheer,
• Peter Nielsen,
• Jörg Heeren,
• Stephen G. Hickey and
• Alexander Eychmüller

Beilstein J. Nanotechnol. 2014, 5, 2383–2387, doi:10.3762/bjnano.5.247

• the production of very small batches of 5 nmol QDs without loss in the fluorescence quality was developed. Subsequently, the radio-labelled QDs were phase transferred by encapsulation into an amphiphilic polymer. γ-counting of the radioactivity provided confirmation of the successful labelling and

• . Therefore, an encapsulation and phase transfer method described by Shtykova et al. was used to introduce the QDs, stabilized by nonpolar ligands, into an amphiphilic polymer [14]. Under UV illumination, similar emission colours for both, the hydrophilic, encapsulated and the hydrophobic QDs were detected

• , which is evidence for the success of the encapsulation as well as the fact that nanoparticles remain uncompromised during the wrapping procedure. However, it was found by γ-counting of radioactivity that a dramatic decrease of about 90% occurred during the encapsulation step. Initial studies suggest

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

• particles are diluted in biological media [102]. On the contrary, the encapsulation of isotropic nanoparticles in a silica shell was established, which is advantageous because of the extraordinary stability of silica and its well-known surface chemistry that allows further functionalization. Furthermore

• formation of the iron oxide component. Wu et al. pointed out that a thiol passivation of the surface is crucial for retaining the Janus character due to the two different surfaces [38]. This was demonstrated by complete encapsulation of Au@Fe3O4 as well as Ag@Fe2O3 nanoparticles with a silica shell [103

• -mediated synthesis of Au@MOx heterodimers, subsequent encapsulation with silica and functionalization of the SiO2-shell. Adapted with permission from [39]. Copyright 2014 American Chemical Society. Acknowledgements This research was supported by the Deutsche Forschungsgemeinschaft through the Priority

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

• particles of iron oxide (USPIO) are used as contrast agents in magnetic resonance imaging, their encapsulation into the protein matrix enables the synthesis of diagnostic and theranostic agents by surface modification and co-encapsulation of active pharmaceutical ingredients. The present investigation deals

• the present study, nanoparticles consisting of HSA were formed by ethanolic desolvation [9]. These nanocarriers were used matrix system for the encapsulation of USPIO. USPIO have been efficiently applied as contrast agents for magnetic resonance imaging and allow the tracking of nanoparticles in vivo

• transmission electron microscopy Electron microscopy of USPIO HSA hybrid particles revealed encapsulation of the modified USPIO into the protein shell (Figure 4). HSA provides a matrix structure of increasing electron density with increasing amount of crosslinker present during the preparation process. For

Biopolymer colloids for controlling and templating inorganic synthesis

• Laura C. Preiss,
• Katharina Landfester and
• Rafael Muñoz-Espí

Beilstein J. Nanotechnol. 2014, 5, 2129–2138, doi:10.3762/bjnano.5.222

• molybdenum oxide clusters, which were shown to be active as catalysts for selective alcohol oxidation. Similarly, Ganesan and Gedanken [74] had prepared tungsten(VI) oxide nanoparticles through the encapsulation of ammonium metatungstate on chitosan and the subsequent calcination. These particles showed a

Data-adaptive image-denoising for detecting and quantifying nanoparticle entry in mucosal tissues through intravital 2-photon microscopy

• Torsten Bölke,
• Lisa Krapf,
• Regina Orzekowsky-Schroeder,
• Tobias Vossmeyer,
• Jelena Dimitrijevic,
• Horst Weller,
• Anna Schüth,
• Antje Klinger,
• Gereon Hüttmann and
• Andreas Gebert

Beilstein J. Nanotechnol. 2014, 5, 2016–2025, doi:10.3762/bjnano.5.210

• by encapsulation within amphiphilic shells of crosslinked poly(isoprene)-block-poly(ethylene glycol) (PI-b-PEG), following a procedure described in detail previously [25][26][27]. The outer PEG-blocks were exo-functionalized with carboxy groups. After phase transfer, the PI-b-PEG-encapsulated QDs had

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

• intracellular agglomeration of silver nanoparticles is still unknown; however, as reported by Dausend et al. [79] and Harush-Frenkel et al. [80] it is likely that encapsulation in a membrane vesicle (endosome/lysosome) is involved. Different pathways were suggested for the uptake of nanoparticles into cells

Non-covalent and reversible functionalization of carbon nanotubes

• Antonello Di Crescenzo,
• Valeria Ettorre and
• Antonella Fontana

Beilstein J. Nanotechnol. 2014, 5, 1675–1690, doi:10.3762/bjnano.5.178

• attachment of molecular pendants to the Csp2 backbone [19][20] and ii) non-covalent functionalization by adsorption of molecules onto the nanotube surface [21]. Alternatively, in order to use CNTs for elected applications, encapsulation of molecules in the inner empty cavity of the nanotubes has been

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

• nanocrystals Encapsulation of nanocrystals was achieved as described [37] with slight modifications: 2 mL poly(maleic anhydride-alt-1-octadecene) (PMAOD) solution (concentration: 0.01 g/mL in CHCl3) were added to a solution of either 2 mg oleic acid stabilized SPIO, QDs or 59Fe-SPIOs [21] dissolved in 2 mL

Model systems for studying cell adhesion and biomimetic actin networks

• Dorothea Brüggemann,
• Johannes P. Frohnmayer and
• Joachim P. Spatz

Beilstein J. Nanotechnol. 2014, 5, 1193–1202, doi:10.3762/bjnano.5.131

• encapsulation. Later, inverted emulsion was used to polymerise actin at the inner membrane of larger vesicles with sizes between 1 and 8 μm. This approach preserved the integrity of actin, and polymerisation was triggered by ATP and high salt concentrations [62]. When a continuous actin shell formed at the

• technique was extended further to encapsulate filaments of bacterial cytoskeletal proteins, such as MreB and FtsZ, into liposomes [64][65]. Compared to other vesicle preparation techniques, this approach offers a high encapsulation efficiency and good control over protein entrapment without a loss of

• regulation of morphological changes in such synthetic cells was explained by a balance of actomyosin cortical tension and mechanical resistance to rupture [71]. For the functional encapsulation of cytoskeletal proteins into lipid vesicles high physiological salt levels are mandatory and the fabrication

Optimizing the synthesis of CdS/ZnS core/shell semiconductor nanocrystals for bioimaging applications

• Li-wei Liu,
• Si-yi Hu,
• Ying Pan,
• Jia-qi Zhang,
• Yue-shu Feng and
• Xi-he Zhang

Beilstein J. Nanotechnol. 2014, 5, 919–926, doi:10.3762/bjnano.5.105

• to the dendrimer template for preparing the QDs [33][34][35]. Because of the encapsulation, there is a change in the dielectric constant of the surrounding medium of the QDs, which can also be accounted for a shift of the emission wavelength. Extensive research on the properties of QDs revealed that

Cyclodextrin-poly(ε-caprolactone) based nanoparticles able to complex phenolphthalein and adamantyl carboxylate

• Daniela Ailincai and
• Helmut Ritter

Beilstein J. Nanotechnol. 2014, 5, 651–657, doi:10.3762/bjnano.5.76

• phase, which may serve as an example for the uptake of a drug. The formed nanoparticles were characterized in terms of sizes and morphology by both DLS and TEM. Keywords: click reaction; complexation; cyclodextrin; encapsulation; nanoparticles; Introduction The development of new nanoscale systems for

• the encapsulation of drugs or imaging agents, which could be used in the treatment, localization or diagnosis of diseased tissues, represents one of the most interesting aims for researchers working in the realm of biochemistry. A lot of such systems have been reported in the past years, including

• covalently attached. The nanoparticles have been characterized in terms of morphology and diameter by both DLS measurements and TEM. Umbelliferone, a hydrophobic molecule, was not included in the cavity of the CD moiety according to ROESY NMR measurements. However, the encapsulation of umbelliferone in the

Biocalcite, a multifunctional inorganic polymer: Building block for calcareous sponge spicules and bioseed for the synthesis of calcium phosphate-based bone

• Xiaohong Wang,
• Heinz C. Schröder and
• Werner E. G. Müller

Beilstein J. Nanotechnol. 2014, 5, 610–621, doi:10.3762/bjnano.5.72

• , indicating that alginate/chitin, also together with silica [73][74], provides a suitable matrix for the encapsulation of mammalian cells we have recently also embedded SaOS-2 cells into Na alginate that has been supplemented with silica [75][76][77]. Silica displays morphogenetic activity towards SaOS-2

In vitro toxicity and bioimaging studies of gold nanorods formulations coated with biofunctional thiol-PEG molecules and Pluronic block copolymers

• Tianxun Gong,
• Douglas Goh,
• Malini Olivo and
• Ken-Tye Yong

Beilstein J. Nanotechnol. 2014, 5, 546–553, doi:10.3762/bjnano.5.64

• at 10,000 rpm for 10 min and suspended in water. This washing step was repeated 3 times to remove excess CTAB. For AuNRs encapsulation, after three centrifugations, the supernatant were taken out and the AuNRs pellet was left in the centrifuge tube without suspending them in water. A transmission

• PEG-SH and PEO–PPO–PEO molecules resulted in decreased cell viabilities. This may be caused by the impact of forming a thicker coating layer on the AuNRs surface [33]. Many groups have reported on the encapsulation of AuNRs with other polymer coatings to improve the biocompatibility of the rod

• polymer-based encapsulation further facilitates the use of AuNRs as biocompatible in vivo probes. Conclusion In this work, we studied the cytotoxicity, colloidal stability and optical property of AuNRs before and after functionalizing them with PEG-SH and PEO–PPO–PEO molecules. The as-synthesized AuNR

Encapsulation of nanoparticles into single-crystal ZnO nanorods and microrods

• Jinzhang Liu,
• Marco Notarianni,
• Llew Rintoul and
• Nunzio Motta

Beilstein J. Nanotechnol. 2014, 5, 485–493, doi:10.3762/bjnano.5.56

• functional nanoparticles of other materials could be an interesting platform for various applications. We studied the encapsulation of nanoparticles into single-crystal ZnO nanorods by exploiting the crystal growth of ZnO in aqueous solution. Two types of nanodiamonds with mean diameters of 10 nm and 40 nm

• , respectively, and polymer nanobeads with size of 200 nm have been used to study the encapsulation process. It was found that by regrowing these ZnO nanorods with nanoparticles attached to their surfaces, a full encapsulation of nanoparticles into nanorods can be achieved. We demonstrate that our low

• micro-photoluminescence measurement on a single ZnO nanorod containing luminescent nanodiamonds and the spectrum has a different shape from that of naked nanodiamonds, revealing the cavity effect of ZnO nanorod. Keywords: crystal growth; encapsulation; nanoparticles; photoluminescence; ZnO nanorods

Design criteria for stable Pt/C fuel cell catalysts

• Josef C. Meier,
• Carolina Galeano,
• Ioannis Katsounaros,
• Jonathon Witte,
• Hans J. Bongard,
• Angel A. Topalov,
• Claudio Baldizzone,
• Stefano Mezzavilla,
• Ferdi Schüth and
• Karl J. J. Mayrhofer

Beilstein J. Nanotechnol. 2014, 5, 44–67, doi:10.3762/bjnano.5.5

• 360 nm with an average shell thickness of approximately 50 nm. The mesoporous network is intended to provide a good separation and encapsulation of the particles without losing accessibility to the Pt particles. The access is also facilitated by the short diffusion pathways through the shell, which

Ellipsometry and XPS comparative studies of thermal and plasma enhanced atomic layer deposited Al₂O₃-films

• Jörg Haeberle,
• Karsten Henkel,
• Hassan Gargouri,
• Franziska Naumann,
• Bernd Gruska,
• Michael Arens,
• Massimo Tallarida and
• Dieter Schmeißer

Beilstein J. Nanotechnol. 2013, 4, 732–742, doi:10.3762/bjnano.4.83

• been investigated for several applications like surface passivation or encapsulation in organic and inorganic photovoltaic devices [1][2], interfacial buffering for high-k dielectrics [3][4], organic memories [5], and nano-laminates [6] as well as work function modification [7], gas diffusion barrier

A facile synthesis of a carbon-encapsulated Fe₃O₄ nanocomposite and its performance as anode in lithium-ion batteries

• Raju Prakash,
• Katharina Fanselau,
• Shuhua Ren,
• Tapan Kumar Mandal,
• Christian Kübel,
• Horst Hahn and
• Maximilian Fichtner

Beilstein J. Nanotechnol. 2013, 4, 699–704, doi:10.3762/bjnano.4.79

• strategies, such as carbon coatings [7], carbon core–shells [8], nanocomposites [9], nanostructures [10], or nano-encapsulation [11], have recently been explored to circumvent this problem. These strategies apply various synthetic methods [12] such as hydrothermal, coprecipitation, microemulsion, sol–gel

Functionalization of vertically aligned carbon nanotubes

• Eloise Van Hooijdonk,
• Carla Bittencourt,
• Rony Snyders and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2013, 4, 129–152, doi:10.3762/bjnano.4.14

• constraint for the growth of CNTs is the poisoning of the catalyst due to encapsulation by amorphous carbon. In 2004, Hata et al. [26] reported the growth of VA-CNTs with millimeter length (Figure 3). By adding a small amount of an oxidizer during the CVD synthesis the poisoning of catalyst nanoparticles is