pH-Triggered release from surface-modified poly(lactic-co-glycolic acid) nanoparticles

• Manuel Häuser,
• Klaus Langer and
• Monika Schönhoff

Beilstein J. Nanotechnol. 2015, 6, 2504–2512, doi:10.3762/bjnano.6.260

• fulfilling this criterion is poly(lactic-co-glycolic acid) (PLGA), a copolymer consisting of lactic acid and glycolic acid, which has been approved by the authorities to be suitable for pharmaceutical application [5]. Nanoparticles of an appropriate size can be reliably assembled via an emulsion diffusion

• a pH stimulus. Nanoparticle preparation: PLGA nanoparticles were prepared by a modified emulsion diffusion method. The addition of a stabilizing agent is generally favoured due to increased final particle stability. Here, poly(vinyl alcohol) (PVA) was used for particle preparation since it has

• proven to have outstanding emulsification properties and a low toxicity at the same time. In brief, 500 mg of PLGA was dissolved in 5 mL ethyl acetate. After addition of 10 mL aqueous PVA solution (10 mg/mL), the obtained emulsion was mixed using an Ultra Turrax T25 homogenization device (IKA Werke GmbH

Radiation losses in the microwave K_u band in magneto-electric nanocomposites

• Talwinder Kaur,
• Sachin Kumar,
• Jyoti Sharma and
• A. K. Srivastava

Beilstein J. Nanotechnol. 2015, 6, 1700–1707, doi:10.3762/bjnano.6.173

• explained. Further studies revealed that the prepared material is a nanocomposite. FTIR spectra show the presence of expected chemical structures such as C–H bonds in a ring system at 1512 cm−1. Keywords: emulsion polymerization; magneto-electric composite; radiation loss; vector network analyser

• paper, we have used the versatile citrate precursor method to synthesize La–Co-substituted barium hexaferrite. Lanthanum and cobalt are used as substituents to enhance the magnetic properties of barium hexaferrite and then emulsion polymerization is employed for the synthesis of nanocomposites. The

• /min to remove impurities. Then the precursor material is calcined at 900 °C at a rate of 23 °C/min for 5 h. An aqueous solution (0.3 M) of dodecyl benzene sulfonic acid (DBSA) is added to a barium hexaferrite solution (0.1 M) to form an emulsion. Aniline (0.1 M) is added to the solution. The magnetic

PLGA nanoparticles as a platform for vitamin D-based cancer therapy

• Maria J. Ramalho,
• Joana A. Loureiro,
• Bárbara Gomes,
• Manuela F. Frasco,
• Manuel A. N. Coelho and
• M. Carmo Pereira

Beilstein J. Nanotechnol. 2015, 6, 1306–1318, doi:10.3762/bjnano.6.135

• cell growth, cell cycle arrest and morphological changes. Results Nanoparticle physicochemical properties PLGA NPs were prepared by a single emulsion solvent evaporation method and stabilized with Pluronic®F127. The obtained results for mean the diameter, polydispersity index (PDI) and zeta potential

• , as expected, due to their carboxylic end groups (Table 1). The single emulsion solvent evaporation method allowed the encapsulation of vitamin D3 in the PLGA NPs. The obtained results for the mean diameter, PDI, zeta potential, encapsulation efficiency and loading capacity values for the PLGA NPs

• formulated as promising delivery systems to improve the therapeutic potential of calcitriol. The PLGA NPs were prepared by a single emulsion solvent evaporation method and stabilized with Pluronic®F127. The prepared NPs exhibited mean diameters smaller than 200 nm and negative zeta potential. The observed

High photocatalytic activity of V-doped SrTiO₃ porous nanofibers produced from a combined electrospinning and thermal diffusion process

• Panpan Jing,
• Wei Lan,
• Qing Su and
• Erqing Xie

Beilstein J. Nanotechnol. 2015, 6, 1281–1286, doi:10.3762/bjnano.6.132

• ), 1.0 g CH3COOH and 1.0 g C2H5OH under vigorous stirring. Meanwhile, a Sr(NO3)2 solution was also prepared by dissolving 0.147 g pf SrCO3 in 1.3 g of dilute HNO3 (15%). About 6 h later, a homogenous spinning emulsion with stoichiometric Sr2+ and Ti4+ was obtained by sufficiently mixing the above

• solutions. This was then transferred to a glass syringe with a stainless steel needle (inner diameter ≈0.4 mm) for electrospinning. The distance and voltage from the tip of needle to the collector were set at 20 cm and 17 kV, respectively. The feeding rate of the emulsion was set at 0.5 mL/h. After

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

• nanocomposite material composed of a magnetic silica core and a fluorescent shell by combining two different techniques, namely heterocoagulation and soap-free emulsion polymerization. The N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TSA)-modified Fe3O4 NPs were prepared by the Massart method and

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

• functionalized polystyrene nanoparticles as described in [18]) or by a combination of miniemulsion and emulsion/solvent evaporation techniques (PLLA nanoparticles without and with magnetite, as described in [19][20]). In all cases, SDS was used as a surfactant for the synthesis or formation of the nanoparticles

• finding should be further investigated. Experimental Particle synthesis Polystyrene particles were obtained via the miniemulsion process as previously described in [18]. Polylactide particles were obtained by a combination of miniemulsion and emulsion/solvent evaporation techniques as previously described

Overview about the localization of nanoparticles in tissue and cellular context by different imaging techniques

• Anja Ostrowski,
• Daniel Nordmeyer,
• Alexander Boreham,
• Cornelia Holzhausen,
• Lars Mundhenk,
• Christina Graf,
• Martina C. Meinke,
• Annika Vogt,
• Sabrina Hadam,
• Jürgen Lademann,
• Eckart Rühl,
• Ulrike Alexiev and
• Achim D. Gruber

Beilstein J. Nanotechnol. 2015, 6, 263–280, doi:10.3762/bjnano.6.25

• microscope (0.2 µm) and the grain size of the emulsion [69]. This technique has previously been used, for example, for the localization of specific nucleic acid sequence, e.g., chromosomes or viral infections, by in situ hybridization employing radiolabeled nucleic acid probes [70]. We reasoned that this

• autoradiographic emulsion. The slides were exposed for several days and finally fixed with a commercially available fixator for photographic films [56]. Autoradiography can also be adjusted for electron microscopy, EMA, by selecting emulsions with more appropriate grain diameter, tracking characteristics and

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

• emulsion polymerization has been developed, in which additional monomer like styrene, isoprene and divinylbenzene are added as a cross-linking reagent after the micellar encapsulation and polymerized in the hydrophobic core [26]. The monomers react with the double bonds of the PI forming a covalently

• coupled dense shell. Figure 5 shows the whole encapsulation process, including the possible cross-linking and seeded emulsion polymerization steps. A very powerful and sensitive tool to test the density of the nanocontainers is fluorescence quenching with small organic molecules or ions to simulate

• micelles indicating hindered diffusion towards the QD and therefore a denser shell [23]. A strong enhancement of the density could also be observed in the case of QDs stabilized by emulsion polymerization [26]. Finally, the used polymers and ratios between QDs and the polymer have a strong influence on the

Manganese oxide phases and morphologies: A study on calcination temperature and atmospheric dependence

• Matthias Augustin,
• Daniela Fenske,
• Ingo Bardenhagen,
• Anne Westphal,
• Martin Knipper,
• Thorsten Plaggenborg,
• Joanna Kolny-Olesiak and
• Jürgen Parisi

Beilstein J. Nanotechnol. 2015, 6, 47–59, doi:10.3762/bjnano.6.6

• of 200 kV was used. The samples for TEM and HR-TEM measurements were prepared by depositing a drop of an ethanol emulsion of the powder on a carbon-coated copper grid and drying at room temperature. Scanning electron microscopy (SEM) was carried out with an Oxford INCA system employing a PentaFET

• Precision INCA X-act detector integrated into the Hitchai S-3200N microscope. The sample was prepared by depositing an ethanol emulsion of the sample onto an Al substrate and drying at room temperature. For X-ray diffraction (XRD), a PANalytical X’Pert Pro MPD diffractometer was used operating with Cu Kα

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

• Janus particles [25]. The effectiveness of this technique of selective functionalization was shown by Perro and co-workers applying a Pickering emulsion of wax-in-water to obtain a large amount of Janus silica particles with a diameter below 100 nm (Figure 3c) [26]. Nevertheless, dumbbell-shaped

• complex core (IPEC), (c) classical Pickering emulsion technique, (d) different topologies of Janus particles: snowman-, acorn-, and dumbbell-like nanoparticles (top to bottom), (e) microfluidic photo-polymerization system, and (f) electrospinning technique with a bi-phasic nozzle. Reproduced with

Imaging the intracellular degradation of biodegradable polymer nanoparticles

• Anne-Kathrin Barthel,
• Martin Dass,
• Melanie Dröge,
• Jens-Michael Cramer,
• Daniela Baumann,
• Markus Urban,
• Katharina Landfester,
• Volker Mailänder and
• Ingo Lieberwirth

Beilstein J. Nanotechnol. 2014, 5, 1905–1917, doi:10.3762/bjnano.5.201

• were composed of poly(L-lactic acid) (PLLA), decorated with approximately 25 nm-sized magnetite nanoparticles, prepared by combining miniemulsion and emulsion–solvent evaporation techniques. The particles were labeled with the fluorescent dye, N-(2,6-diisopropylphenyl)perylene-3,4-dicarboximide (PMI

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

• . For temperatures below 15 °C a transformation into spiderweblike or ringlike networks was observed (Figure 4) [60]. This polymorphism was also found to depend on the vesicle size. Pautot et al. developed an inverted emulsion technique, which assembles two independently formed lipid monolayers into

• 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

Insect attachment on crystalline bioinspired wax surfaces formed by alkanes of varying chain lengths

• Elena Gorb,
• Sandro Böhm,
• Nadine Jacky,
• Louis-Philippe Maier,
• Kirstin Dening,
• Sasha Pechook,
• Boaz Pokroy and
• Stanislav Gorb

Beilstein J. Nanotechnol. 2014, 5, 1031–1041, doi:10.3762/bjnano.5.116

• ) that cover hairy pads, both pad types can maximize the possible contact area with various substrate profiles (reviews [2][4][5]). Additionally, insect pads release a secretory fluid, which is most probably a micro-emulsion containing water-soluble and lipid-soluble fractions, onto a contact zone [2][6

Antimicrobial nanospheres thin coatings prepared by advanced pulsed laser technique

• Alina Maria Holban,
• Valentina Grumezescu,
• Alexandru Mihai Grumezescu,
• Bogdan Ştefan Vasile,
• Roxana Truşcă,
• Rodica Cristescu,
• Gabriel Socol and
• Florin Iordache

Beilstein J. Nanotechnol. 2014, 5, 872–880, doi:10.3762/bjnano.5.99

• showed no concavities or distortions on their surface within an average diameter of 1 μm of the deposited spheres. It is noteworthy that the microspheres maintain their initial size and do not show an aggregative behavior [34]. All these type of microspheres have been prepared by an oil-in-water emulsion

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• nanocrystal by micro-emulsion under ultrasound [57]. Co-axial arrays of CdS/TiO2 core/shell structures were also reported to be fabricated by an anodic aluminium oxide template [58]. This type of configuration can not only protect the quantum dots from photocorrosion, but also increases the contact interface

Colloidal lithography for fabricating patterned polymer-brush microstructures

• Tao Chen,
• Debby P. Chang,
• Rainer Jordan and
• Stefan Zauscher

Beilstein J. Nanotechnol. 2012, 3, 397–403, doi:10.3762/bjnano.3.46

• nanoscale, by changing the sphere diameter of the colloid mask. Spherical particles are commercially available with a wide range of sizes and types, or can be synthesized, e.g., by emulsion polymerization for polymer latex spheres or by controlled precipitation for inorganic oxides [12]. Patterned polymer

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

• , Germany Department of Solid State Physics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany Central Facility of Electron Microscopy, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany 10.3762/bjnano.2.50 Abstract The benefits of miniemulsion and emulsion polymerization are

• combined in a seeded emulsion polymerization process with functional seed particles synthesized by miniemulsion polymerization. A systematic study on the influence of different reaction parameters on the reaction pathway is conducted, including variations of the amount of monomer fed, the ratio of

• initiator to monomer and the choice of surfactant and composition of the continuous phase. Critical parameters affecting the control of the reaction are determined. If carefully controlled, the seeded emulsion polymerization with functional seed particles yields monodisperse particles with adjustable size

Review and outlook: from single nanoparticles to self-assembled monolayers and granular GMR sensors

• Alexander Weddemann,
• Inga Ennen,
• Anna Regtmeier,
• Camelia Albon,
• Annalena Wolff,
• Katrin Eckstädt,
• Nadine Mill,
• Michael K.-H. Peter,
• Jochen Mattay,
• Carolin Plattner,
• Norbert Sewald and
• Andreas Hütten

Beilstein J. Nanotechnol. 2010, 1, 75–93, doi:10.3762/bjnano.1.10

• , larger ones by TOPO. The dendrimer has a very high dissociation constant which results in a strong binding to the metal atoms and, therefore, in a slow growth. 1.2 Alternative methods 1.2.1 Micro emulsion and magnetotactic bacteria Another method for the synthesis of nanoparticles is the micro emulsion

• hydrophobic tails. Such micelles have a size of 1 to 50 nm depending on the tenside concentration [18]. The precursor is confined within these defined droplets which may, thus, act as nanoreactors in which particle growth is initiated. A typical result obtained by the use of an isopropanol/water emulsion and

• cetyltrimethylammonium bromide (CTAB) as a tenside is shown in Figure 4(a); the reducing agent is sodium borohydride. While micro emulsion allows for much lower temperatures during the synthesis, stabilizing tensides usually need to be injected after the actual growth. Therefore, the additional control of the particle

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

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

Beilstein J. Nanotechnol. 2010, 1, 24–47, doi:10.3762/bjnano.1.5

• present contribution. It is worth noting, however, that in the interim the carrier principle has also been transferred to spherical colloidal polystyrene (PS) particles which can be loaded with various metal precursors by emulsion and miniemulsion methods [57][58]. 1.2 Polymers and precursors In the