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

• bifunctional or multi-dentate ligands/polymers or the formation of amphiphilic micelles while maintaining the original hydrophobic ligand shell. However, all these strategies suffer from the assumption that the ligand coating is neither densely packed nor static with regards to ligand exchange when the

Anticancer efficacy of a supramolecular complex of a 2-diethylaminoethyl–dextran–MMA graft copolymer and paclitaxel used as an artificial enzyme

• Yasuhiko Onishi,
• Yuki Eshita,
• Rui-Cheng Ji,
• Masayasu Onishi,
• Takashi Kobayashi,
• Masaaki Mizuno,
• Jun Yoshida and
• Naoji Kubota

Beilstein J. Nanotechnol. 2014, 5, 2293–2307, doi:10.3762/bjnano.5.238

• represent an outstanding drug delivery method [1][2][3]. Recent detailed research of Maysinger et al. measuring the intracellular distribution of fluorescently labeled polymer micelles by using confocal laser scanning microscopy has shown the effect of a drug administered with a polymer DDS. As for polymer

• micelles carrying a drug, they have been shown to be transported to and act on not only endosomes and lysosomes but also the Golgi body and mitochondria [4]. A block copolymer micelle can be used to deliver a hydrophobic drug as a nanocarrier with water-soluble biological affinity. Knowledge of the

• cellular distribution of micelles is required to enable the selective delivery of a drug to a specific target at the subcellular level [4]. By means of triple-labeling confocal microscopy of living cells, Savic et al. identified the exact cellular targets of block copolymer micelles, i.e., several

Influence of stabilising agents and pH on the size of SnO₂ nanoparticles

• Olga Rac,
• Patrycja Suchorska-Woźniak,
• Marta Fiedot and
• Helena Teterycz

Beilstein J. Nanotechnol. 2014, 5, 2192–2201, doi:10.3762/bjnano.5.228

• were obtained by combining a spray pyrolysis method and annealing carried out under atmospheric pressure. The subject of the synthesis of SnO2 nanoparticles in aqueous solution rarely occurs in the literature. SnO2 colloidal synthesis in cetyltrimethylammonium bromide (CTAB) micelles (where tin

• metal oxides occurring in polymeric micelles [20]. The second theory, although less popular, describes the stabilisation of polymers by molecules that results from the polymerisation of monomers which occur in the presence of nanoparticles. In this article, synthetic polymers were used as stabilisers

• particles attach to the polymer chain and do not form micelles. In contrast, when the concentration is increased to the critical micelle concentration (CMC) point, the micelles are formed in the solution and bind to the active groups of the polymer. Upon further increase of the amount of Triton, the polymer

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

• , micelles, and vesicles, and on the other hand continuous scaffolds generated by gelling biopolymers. Keywords: biomacromolecules; biopolymer; colloid; nanoparticle; organic–inorganic hybrid; template; Introduction During the natural synthesis of inorganic matter in living organisms, referred to as

• “soft templates”, two subgroups can be considered: (C1) Biopolymer-stabilized spherical geometries (stabilized droplets, micelles, and vesicles) that confine the inorganic formation. (C2) Biopolymer structures acting as “scaffolds”, with more complex geometries than simple spheres. This is typically the

• as “soft templates” C1. Biopolymer-stabilized simple geometries (droplets, micelles, and vesicles): Surface-active polymers can assemble in solution and in heterophase systems to form defined geometries, most typically spherical, such as micelles, vesicles, or even stabilized droplets. As in the case

The impact of the confinement of reactants on the metal distribution in bimetallic nanoparticles synthesized in reverse micelles

• Concha Tojo,
• Elena González and
• Nuria Vila-Romeu

Beilstein J. Nanotechnol. 2014, 5, 1966–1979, doi:10.3762/bjnano.5.206

• the chemical reduction rate, but also on the intermicellar exchange rate. Furthermore, intermicellar exchange causes the accumulation of slower precursors inside the micelles, which favors chemical reduction. As a consequence, slower reduction rates strongly correlate with the number of reactants in

• this confined media. On the contrary, faster reduction rates are limited by the intermicellar exchange rate and not the number of reactants inside the micelles. As a result, different precursor proportions lead to different sequences of metal reduction, and thus the arrangement of the two metals in the

• the same micelle due to micelle collisions and coalescence. The chemical reaction can then take place to form precipitates of nanometric size, which remain confined to the interior of reverse micelles. This approach has been used to prepare a variety of nanomaterials [6][11][12][13][14][15] that often

Towards bottom-up nanopatterning of Prussian blue analogues

• Virgile Trannoy,
• Marco Faustini,
• David Grosso,
• Sandra Mazerat,
• François Brisset,
• Alexandre Dazzi and
• Anne Bleuzen

Beilstein J. Nanotechnol. 2014, 5, 1933–1943, doi:10.3762/bjnano.5.204

• samples resulting from this first step and corresponding to the different thicknesses are called Au10, Au20 and Au50 in the following (see below in Table 1). The second step is the deposition by dip-coating of an ethanolic solution of titanium molecular species containing block copolymers micelles that

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

• 18 carbon atoms (NTA) do arrange into half-cylinders oriented parallel to the tube axis (see Figure 3, arrangement A) highlighting the crucial role of supramolecular assembling for CNT-dispersant interactions. The environment of nanotubes in SDS micelles was modeled also by O’Connell et al. [64

• ] through molecular dynamics simulations run for 0.4 ns. The nanotube represented the core of a SDS cylindrical micelles were the hydrophobic tails of SDS molecules could adopt a wide range of orientations with respect to the tube (see Figure 3, arrangement B). As no water density was observed in the

• induced by the surfactant micelles on large colloidal particles. Examples of polymers that favor CNTs dispersion in water are countless. This review is not intended to list all of the investigated polymers, nevertheless it is worth mentioning that the majority of polymers and block copolymers have been

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

• to positively charged NPs [121][122]. iii) Lipids present in membranes or second-messenger lipids wrap around NPs driven by hydrophilic/hydrophobic interaction and often result in formation of micelles [123][124]. iv) Thiols, present in glutathione or reduced proteins bind to the surface of noble

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

• an important entry route into the human body. Therefore, it is crucial to investigate biological responses of the body to nanocrystals to avoid harmful side effects. In recent years, we established a system to embed nanocrystals with a hydrophobic oleic acid shell either by lipid micelles or by the

• type mice, we show that 30 min after injection polymer-coated nanocrystals are primarily taken up by liver sinusoidal endothelial cells. In contrast, by using wild type, Ldlr-/- as well as Apoe-/- mice we show that nanocrystals embedded within lipid micelles are internalized by Kupffer cells and, in a

• haemolysis or nanoparticle uptake [13][14]. In most studies so far, complex surface modification was carried out to achieve water-solubility of hydrophobic QDs or SPIOs [15][16]. Another way to make nanocrystals hydrophilic is the embedding of QDs or SPIOs into the core of lipid micelles [17][18][19]. After

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

• confirmed by specific binding to fibrinogen [33]. Triton X-100 is another detergent that is widely used for the reconstitution of numerous membrane proteins into liposomes since the 1980s [32][35][36]. This detergent has the tendency to form large micelles, which cannot be removed by dialysis. An efficient

• proteins like bacteriorhodopsin and the ferrichrome transport protein FhuA into GUVs with lipid mixtures representative of cellular plasma membranes [51]. Reconstitution was either performed with proteins solubilised in detergent micelles, with proteoliposomes or purified native membranes. This method

Nanodiamond-DGEA peptide conjugates for enhanced delivery of doxorubicin to prostate cancer

• Amanee D Salaam,
• Patrick Hwang,
• Roberus McIntosh,
• Hadiyah N Green,
• Ho-Wook Jun and
• Derrick Dean

Beilstein J. Nanotechnol. 2014, 5, 937–945, doi:10.3762/bjnano.5.107

• ]. Liang et al. demonstrated that DOX-loaded micelles can efficiently use the tumor-targeting function of RGD sequence to deliver the drug into HeLa cells [38]. Tian et al. showed that iRGD exosomes delivered DOX specifically to tumor tissues and inhibited tumor growth without overt toxicity [39]. Zhou et

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

• intensity, stronger stability and exhibited a longer lifetime compared to uncapped CdS. The CdS/ZnS nanocrystals were stabilized in Pluronic F127 block copolymer micelles, offering an optically and colloidally stable contrast agents for in vitro and in vivo imaging. Photostability test exhibited that the

• ZnS protective shell not only enhances the brightness of the QDs but also improves their stability in a biological environment. An in-vivo imaging study showed that F127-CdS/ZnS micelles had strong luminescence. These results suggest that these nanoparticles have significant advantages for bioimaging

• novel integrative strategy that produces bioconjugated CdS/ZnS QDs for the use in bioimaging. In this study, we report a rapid and straightforward method for formulating CdS/ZnS QDs, encapsulated CdS/ZnS QDs in a hydrophobic core provided by block copolymer (Pluronic F127) micelles for bioimaging. The

Cyclic photochemical re-growth of gold nanoparticles: Overcoming the mask-erosion limit during reactive ion etching on the nanoscale

• Burcin Özdemir,
• Axel Seidenstücker,
• Alfred Plettl and
• Paul Ziemann

Beilstein J. Nanotechnol. 2013, 4, 886–894, doi:10.3762/bjnano.4.100

• distance within a given periodic arrangement. 5) The maximizing of defect-free domain sizes of such NP lattices. A relative simple and affordable approach that nevertheless addresses all the above requirements is based on the self-organization of organic carrier systems such as colloids or reverse micelles

• ] carriers. In the following we focus exclusively on Au-precursor (HAuCl4) loaded diblock-copolymers [poly(styrene)(PS)-block-poly(2-vinylpyridine)(P2VP)], which is commercially available from Polymer Source Inc. Canada] that form reverse micelles in toluene. Details on preparing the solution, the dip

• given in parentheses are a measure of each block length) the size (diameter) of the finally obtained Au NP are completely determined by the amount of precursor salt added to the solution. By prolonged stirring, the micelles will be homogeneously loaded with precursor to deliver Gaussian size

Photocatalytic antibacterial performance of TiO₂ and Ag-doped TiO₂ against S. aureus. P. aeruginosa and E. coli

• Kiran Gupta,
• R. P. Singh,
• Ashutosh Pandey and
• Anjana Pandey

Beilstein J. Nanotechnol. 2013, 4, 345–351, doi:10.3762/bjnano.4.40

• -catalyzed sol–gel process [23] starting from titanium(IV) tetrabutoxide (2.94 mM) and using 5 mL of water (pH 2) in the presence of toluene as solvent containing 1% aerosol-OT (reverse micelles) under stirring for 1 h: After gelation, the gel was dried at 100 °C in an oven for 24 h; white TiO2 nanosized

• mM) using 5 mL of water (pH 2) in presence of toluene as solvent containing 1% aerosol-OT (reverse micelles). The appropriate concentration of silver salt (3% or 7%) in 0.5 mL deionized water was dropwise added to the reaction mixture under stirring. After gelation, the nanoparticles were allowed to

Guided immobilisation of single gold nanoparticles by chemical electron beam lithography

• Patrick A. Schaal and
• Ulrich Simon

Beilstein J. Nanotechnol. 2013, 4, 336–344, doi:10.3762/bjnano.4.39

• -assembly of micelles loaded with HAuCl4 and subsequent reduction by hydrogen plasma [8]. Such assembly protocols are more facile, but are limited to the formation of self-forming periodic patterns, which are typically of hexagonal symmetry [8][9][10]. In order to increase the structural variability, guided

Nanoscopic surfactant behavior of the porin MspA in aqueous media

• Ayomi S. Perera,
• Hongwang Wang,
• Tej B. Shrestha,
• Deryl L. Troyer and
• Stefan H. Bossmann

Beilstein J. Nanotechnol. 2013, 4, 278–284, doi:10.3762/bjnano.4.30

• in aqueous phase. Engelhardt et al. have established by using high-resolution TEM that MspA forms micelles and linear aggregates on surfaces showing a zipper-like pattern in the absence of surfactants, and that MspA is able to reconstitute in dimyristoyl phosphatidylcholine (DMPC) vesicles in the

• of surfactants forming spherical or ellipsoidal micelles. To our surprise, TEM characterization of MspA aggregates clearly indicated the formation of vesicles (Figure 4). However, vesicles are typically formed by surfactant bilayers featuring a packing parameter in the range of 0.5 to 1.0 [25]. This

• and positive charges at the outer surface of MspA is shown in Figure 1B and Figure 1C. The experimental finding that MspA forms vesicles and not micelles under the described conditions clearly indicates that there exist additional forces in supramolecular MspA aggregates, which are hydrogen bonding

Controlled positioning of nanoparticles on a micrometer scale

• Fabian Enderle,
• Oliver Dubbers,
• Alfred Plettl and
• Paul Ziemann

Beilstein J. Nanotechnol. 2012, 3, 773–777, doi:10.3762/bjnano.3.86

• arranged in arrays of a certain geometry. For this purpose, a method is introduced combining the bottom-up self-organization of precursor-loaded micelles providing Au nanoparticles (NPs), with top-down electron-beam lithography. As an example, 13 nm Au NPs are arranged in a square array with interparticle

• them as masks for subsequent etching procedures to transfer the NP pattern into their supporting substrate. In this respect, the notion of a nanoparticle should include as well colloids and micelles since their use for patterning is more widely spread [7][8][9][10][11][12]. Of course, in addition to

• distances well above 1 µm. It is exactly this problem of combining the nano- with the micro-scale that is the focus of the present contribution. In the following approach, NPs prepared by exploiting the self-organization of precursor loaded micelles formed from diblock-copolymers play a major role as a

Magnetic-Fe/Fe₃O₄-nanoparticle-bound SN38 as carboxylesterase-cleavable prodrug for the delivery to tumors within monocytes/macrophages

• Hongwang Wang,
• Tej B. Shrestha,
• Matthew T. Basel,
• Raj K. Dani,
• Gwi-Moon Seo,
• Sivasai Balivada,
• Marla M. Pyle,
• Heidy Prock,
• Olga B. Koper,
• Prem S. Thapa,
• David Moore,
• Ping Li,
• Viktor Chikan,
• Deryl L. Troyer and
• Stefan H. Bossmann

Beilstein J. Nanotechnol. 2012, 3, 444–455, doi:10.3762/bjnano.3.51

• vehicles that can incorporate SN38 by chemical conjugation or physical entrapment. Polymeric micelles, liposomes and thermally sensitive polymer-based nanoparticles, as well as multi-armed-PEG-functionalized nanographene oxide, have been used as carriers for the delivery of SN38 into biological systems [21

• ][22][23][24][25][26]. SN38-loaded polymeric micelles (NK012) have been used in preclinical and clinical studies against various types of cancer. Specific accumulation of this formulation to the tumor site by the EPR effect (enhanced permeation and retention), and sustained release of SN38 in tumor

Mesoporous MgTa₂O₆ thin films with enhanced photocatalytic activity: On the interplay between crystallinity and mesostructure

• Jin-Ming Wu,
• Igor Djerdj,
• Till von Graberg and
• Bernd M. Smarsly

Beilstein J. Nanotechnol. 2012, 3, 123–133, doi:10.3762/bjnano.3.13

• , the SAXS scattering maxima can still be discerned after calcination up to 1000 °C. Therefore, the present ordered mesoporous MgTa2O6 film possessed a relatively high thermal stability. This property was attributed to the special templating properties of KLE, which forms relatively large micelles

Template-assisted formation of microsized nanocrystalline CeO₂ tubes and their catalytic performance in the carboxylation of methanol

• Jörg J. Schneider,
• Meike Naumann,
• Christian Schäfer,
• Armin Brandner,
• Heiko J. Hofmann and
• Peter Claus

Beilstein J. Nanotechnol. 2011, 2, 776–784, doi:10.3762/bjnano.2.86

• , which form spherical and cylindrical micelles, and which could thus allow for a better contact of the inorganic ceria sol with the electrospun polymer fibres during impregnation. After spray-coating followed by sol–gel transformation to the ceramic green body at 80 °C overnight, the green body was

Surface induced self-organization of comb-like macromolecules

• Konstantin I. Popov,
• Vladimir V. Palyulin,
• Martin Möller,
• Alexei R. Khokhlov and
• Igor I. Potemkin

Beilstein J. Nanotechnol. 2011, 2, 569–584, doi:10.3762/bjnano.2.61

• unusual viscoelastic properties (super-soft elastomers) [5][14], may form micelles as big as 300 nm [15] and have extremely interesting 2D conformational behavior in the adsorbed state [4]. Brush copolymers with diblock and triblock copolymers as side chains can be used for the creation of well defined

• behavior [46][47][48]. Both scaling theory [46][47] and simulations [47][48] predicted that collapse of the main chain with increase of hydrophobicity in densely grafted combs would lead to formation of a necklace of intramolecular starlike micelles, with hydrophobic corelike domains connected by extended

• bridges and hydrophilic corona formed by the grafts (Figure 1). Scaling analysis reveals that the formation of finite-size intramolecular micelles happens only in a narrow range of interaction parameters near the transition point. A similar pearl-necklace structure was detected experimentally for core

Nanoscaled alloy formation from self-assembled elemental Co nanoparticles on top of Pt films

• Luyang Han,
• Ulf Wiedwald,
• Johannes Biskupek,
• Kai Fauth,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 473–485, doi:10.3762/bjnano.2.51

• ) substrates, respectively. For this purpose, metallic Co nanoparticles (diameter 7 nm) were prepared with a spacing of 100 nm by deposition of precursor-loaded reverse micelles, subsequent plasma etching and reduction on flat Pt surfaces. The samples were then annealed at successively higher temperatures

• probe microscopy techniques [5], one is left with processes relying on the self-assembly of colloids or micelles [6][7][8]. In the context of magnetic NPs, two prominent examples, both dealing with the preparation of magnetically attractive FePt NPs, which successfully demonstrated fulfillment of the

• orientation of the STO substrates we find a cube-on-cube growth of the Pt film on the STO(100) with orientations Pt(100)||STO(100) and Pt[010]||STO[010]. Co nanoparticles on Pt films The preparation of metal NPs is based on spherical reverse micelles formed by the diblock copolymer poly(styrene)[m]-block-poly

Platinum nanoparticles from size adjusted functional colloidal particles generated by a seeded emulsion polymerization process

• Nicolas Vogel,
• Ulrich Ziener,
• Achim Manzke,
• Alfred Plettl,
• Paul Ziemann,
• Johannes Biskupek,
• Clemens K. Weiss and
• Katharina Landfester

Beilstein J. Nanotechnol. 2011, 2, 459–472, doi:10.3762/bjnano.2.50

• concentrations were below the critical value for micelle formation (cmc). Such concentrations are used in conventional emulsion polymerization and lead to particles nucleated in monomer swollen micelles [13]. Figure 3b and c show representative SEM micrographs of the resulting dispersions. For both cases

Organic–inorganic nanosystems

• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 363–364, doi:10.3762/bjnano.2.41

• the application to pre-patterned substrates acting as templates. In the above example, diblock-copolymers will form spherical micelles within a certain window of block lengths in a properly chosen solvent, and such micelles can be used as carriers for a metal precursor during their self-organization

• loaded micelles or, more generally, colloids, the organic carriers are completely removed after their self-organization by various plasma treatments while the precursor compounds are transformed into metal oxides or, finally, into metals. In this way, hexagonal ordered arrays of metal nanoparticles can

Novel acridone-modified MCM-41 type silica: Synthesis, characterization and fluorescence tuning

• Maximilian Hemgesberg,
• Gunder Dörr,
• Yvonne Schmitt,
• Andreas Seifert,
• Zhou Zhou,
• Robin Klupp Taylor,
• Sarah Bay,
• Stefan Ernst,
• Markus Gerhards,
• Thomas J. J. Müller and
• Werner R. Thiel

Beilstein J. Nanotechnol. 2011, 2, 284–292, doi:10.3762/bjnano.2.33

• decrease of ordering with increasing bulk of the organic groups, although all exhibited very high specific surface areas. As the formation of micelles will strongly depend on the nature of the organic molecule and its concentration, it was decided to keep the amount of precursor 1 at 10 mol % with respect