Wet-spinning of magneto-responsive helical chitosan microfibers

• Dorothea Brüggemann,
• Johanna Michel,
• Naiana Suter,
• Matheus Grande de Aguiar and
• Michael Maas

Beilstein J. Nanotechnol. 2020, 11, 991–999, doi:10.3762/bjnano.11.83

• panel) reveal a fiber diameter of approximately 130 µm and a higher magnification image confirms the coagulation-driven IOP agglomeration in the chitosan fibers (right panel). (C) SEM images obtained from the backscattered electrons show the difference in material contrast between the chitosan matrix

Agglomerates of nanoparticles

• Dieter Vollath

Beilstein J. Nanotechnol. 2020, 11, 854–857, doi:10.3762/bjnano.11.70

• Dieter Vollath NanoConsulting, Primelweg 3, Stutensee 76297, Germany 10.3762/bjnano.11.70 Abstract Nanoparticles tend to agglomerate. The process of agglomeration is ruled by thermodynamics. Depending on the sign of the enthalpy of interaction, ensembles consist of (repelling) poorly agglomerated

• . The exact determination of the size distribution of the agglomerates also gives the maximum size of the agglomerates. These considerations lead to an improved understanding of ensembles of agglomerated nanoparticles. Keywords: agglomeration; enthalpy; entropy; Gibbs entropy; nanoparticles; size

• microscopy of individual particles to analyze their shape or structure, it is necessary to apply a separation process. Earlier, the problem of agglomeration was already discussed in connection with colloids [2][3][4][5][6]. Recently, two studies of the formation of agglomerates of nanoparticles were

Nickel nanoparticles supported on a covalent triazine framework as electrocatalyst for oxygen evolution reaction and oxygen reduction reactions

• Secil Öztürk,
• Yu-Xuan Xiao,
• Dennis Dietrich,
• Beatriz Giesen,
• Juri Barthel,
• Jie Ying,
• Xiao-Yu Yang and
• Christoph Janiak

Beilstein J. Nanotechnol. 2020, 11, 770–781, doi:10.3762/bjnano.11.62

• stabilization of metal nanoparticles and for a good dispersion of active species that are formed upon reduction of coordinated or impregnated metal precursors while minimizing their agglomeration and leaching [35]. In the literature we can find some studies that are focused on CTFs as catalysts for ORR. In the

Structural optical and electrical properties of a transparent conductive ITO/Al–Ag/ITO multilayer contact

• Aliyu Kabiru Isiyaku,
• Ahmad Hadi Ali and
• Nafarizal Nayan

Beilstein J. Nanotechnol. 2020, 11, 695–702, doi:10.3762/bjnano.11.57

• dense particles. After annealing, the film surfaces become smoother and the grain sizes increase, with the IAAI films exhibiting larger grain sizes. Island formation or agglomeration of the Al–Ag metal film on the surface of the annealed IAAI film was not observed. Hence, the IAAI structure is stable at

Identification of physicochemical properties that modulate nanoparticle aggregation in blood

• Ludovica Soddu,
• Duong N. Trinh,
• Eimear Dunne,
• Dermot Kenny,
• Giorgia Bernardini,
• Ida Kokalari,
• Arianna Marucco,
• Marco P. Monopoli and
• Ivana Fenoglio

Beilstein J. Nanotechnol. 2020, 11, 550–567, doi:10.3762/bjnano.11.44

• may indirectly induce platelet aggregation. The interference with the coagulation system is not the only possible mechanism that may induce vascular occlusion, as the NP have a strong tendency to agglomerate also in water. The degree of the agglomeration is controlled by the size, shape and surface

• chemistry of the particles. Strong repulsive electrostatic charges and steric hindrance may stabilize the NPs and prevent agglomeration. In the bloodstream, agglomeration is related to the formation of a biocorona that modifies the electrostatic and steric repulsion among particles [22]. Finally, protein

• –protein interaction may lead to bridging among particles, thus promoting agglomeration [23]. In the present study, a set of six silica and carbon NPs of known size and morphology was used to evaluate the effect of the size and surface properties on the protein corona composition, platelet activation and

Synthesis and enhanced photocatalytic performance of 0D/2D CuO/tourmaline composite photocatalysts

• Changqiang Yu,
• Min Wen,
• Zhen Tong,
• Shuhua Li,
• Yanhong Yin,
• Xianbin Liu,
• Yesheng Li,
• Tongxiang Liang,
• Ziping Wu and
• Dionysios D. Dionysiou

Beilstein J. Nanotechnol. 2020, 11, 407–416, doi:10.3762/bjnano.11.31

• and higher specific surface area compared with its bulk counterpart [11][12]. However, the agglomeration of nanoscale CuO results from the high surface energy and the quick recombination of the photoinduced charge carriers and restricts the photocatalytic activity [13][14]. At present, the

• CuO nanoflakes and significantly alleviated their agglomeration. The lattice fringes with a d spacing of 0.34 nm and 0.25 nm matched well with the (012) plane of tourmaline and the (002) plane of CuO, respectively (Figure 3d,e, inset). There was intimate interfacial contact between CuO and tourmaline

Interactions at the cell membrane and pathways of internalization of nano-sized materials for nanomedicine

• Valentina Francia,
• Daphne Montizaan and
• Anna Salvati

Beilstein J. Nanotechnol. 2020, 11, 338–353, doi:10.3762/bjnano.11.25

• describe some technical challenges concerning in vitro studies of the endocytosis of nano-sized materials. 4.1 Nanoparticle dispersion in biological media: agglomeration and corona formation One of the most important aspects to consider when studying nanoparticle interactions with cells, as well as when

• characterizing the mechanism for their internalization, is the stability over time and the potential agglomeration of nanoparticles in biological media. In fact, agglomeration can strongly affect the corona composition, the interaction with cells, as well as the pathways of internalization [59][184][185]. Thus

• , it is important to characterize the nanoparticle dispersion in the biological media in which the nanomedicine will be applied, and to monitor potential agglomeration and stability over time. Additionally, studies in which nanoparticles are incubated on cells without serum or other biological fluids

Size effects of graphene nanoplatelets on the properties of high-density polyethylene nanocomposites: morphological, thermal, electrical, and mechanical characterization

• Tuba Evgin,
• Alpaslan Turgut,
• Georges Hamaoui,
• Zdenko Spitalsky,
• Nicolas Horny,
• Matej Micusik,
• Mihai Chirtoc,
• Mehmet Sarikanat and
• Maria Omastova

Beilstein J. Nanotechnol. 2020, 11, 167–179, doi:10.3762/bjnano.11.14

• transfer between GnPs and the HDPE matrix, while G2, with a larger size and thickness, demonstrated an effective improvement of the tensile strength of the nanocomposites because G2 achieved a better dispersion with less agglomeration, as seen in SEM images. According to the obtained results, the

• volume fraction of GnP. This may have been due to agglomeration of the GnPs in the polymer matrix [8]. The agglomeration of the GnPs may have increased the molecular mobility and decreased the thermal stability of the polymer nanocomposites [39]. The thermal stability of the nanocomposites was enhanced

Long-term stability and scale-up of noncovalently bound gold nanoparticle-siRNA suspensions

• Anna V. Epanchintseva,
• Julia E. Poletaeva,
• Dmitrii V. Pyshnyi,
• Elena I. Ryabchikova and
• Inna A. Pyshnaya

Beilstein J. Nanotechnol. 2019, 10, 2568–2578, doi:10.3762/bjnano.10.248

• clumping of particles in the suspension can be reversible or irreversible, which leads to the formation of agglomerates or aggregates, respectively, according to the definition of the IUPAC International Committee [28]. All existing methods for the registration of aggregation/agglomeration of particles in

• and Figure 3A). The appearance of rounded clusters of AuNP-siRNA with a diameter of not more than 200 nm was a consequence of aggregation/agglomeration of particles over the course of one day (Figure 3E). The particles in the clusters were arranged in several layers and were distinguishable. The

Formation of metal/semiconductor Cu–Si composite nanostructures

• Natalya V. Yumozhapova,
• Andrey V. Nomoev,
• Vyacheslav V. Syzrantsev and
• Erzhena C. Khartaeva

Beilstein J. Nanotechnol. 2019, 10, 2497–2504, doi:10.3762/bjnano.10.240

• core–shell nanoparticles upon the condensation of silicon atoms onto the core when a copper nanocluster is introduced into a gaseous medium consisting of silicon atoms. In [22], similar particles were obtained by laser ablation of Au nanoparticles onto larger Co-oxide particles and agglomeration with a

Microfluidics as tool to prepare size-tunable PLGA nanoparticles with high curcumin encapsulation for efficient mucus penetration

• Nashrawan Lababidi,
• Valentin Sigal,
• Aljoscha Koenneke,
• Konrad Schwarzkopf,
• Andreas Manz and
• Marc Schneider

Beilstein J. Nanotechnol. 2019, 10, 2280–2293, doi:10.3762/bjnano.10.220

• [43]. Using a PLGA concentration of >10 mg/mL resulted in clogging of the mixing channel due to agglomeration. For concentrations less than 1 mg/mL, we were not able to produce monodisperse PLGA NPs; several peaks ranging from 20 nm up to 100 nm were observed in DLS (data not shown). This was

• colloidal system, thus minimizing NP agglomeration and nucleation growth [40]. Pluronic F68 was proven to be a muco-inert material [11][47] and was therefore chosen as a stabilizer. The addition of Pluronic F68 (1%) resulted in a slight decrease of the NP diameter to ≈70 nm at 0.05 flow rate ratio in

• is dependent on the time available for growth and agglomeration. Aggregation is assumed to happen after the initial formation and it is assumed to depend on the length of the mixing channel [36]. Therefore, adjusting the length of the mixing channel to only allow for nuclei formation should hinder NP

Improved adsorption and degradation performance by S-doping of (001)-TiO₂

• Xiao-Yu Sun,
• Xian Zhang,
• Xiao Sun,
• Ni-Xian Qian,
• Min Wang and
• Yong-Qing Ma

Beilstein J. Nanotechnol. 2019, 10, 2116–2127, doi:10.3762/bjnano.10.206

• . Compared to the S-doped samples at synthesized 180 °C, the SBET of almost all the S-doped samples prepared at 250 °C are reduced, and with values of 81–123 m2g−1 they are close to the values reported in literature [52]. This is mainly ascribed to the agglomeration of the TiO2 particles synthesized at 250

Incorporation of doxorubicin in different polymer nanoparticles and their anticancer activity

• Sebastian Pieper,
• Hannah Onafuye,
• Dennis Mulac,
• Jindrich Cinatl Jr.,
• Mark N. Wass,
• Martin Michaelis and
• Klaus Langer

Beilstein J. Nanotechnol. 2019, 10, 2062–2072, doi:10.3762/bjnano.10.201

• easily degraded into their monomers, lactic acid and glycolic acid. Furthermore, a copolymer composed of polyethylene glycol (PEG) and PLGA (PLGA-PEG) was used for nanoparticle preparation. PEGylated (“stealth”) nanoparticles display prolonged systemic circulation time, because they avoid agglomeration

The influence of porosity on nanoparticle formation in hierarchical aluminophosphates

• Matthew E. Potter,
• Lauren N. Riley,
• Alice E. Oakley,
• Panashe M. Mhembere,
• June Callison and
• Robert Raja

Beilstein J. Nanotechnol. 2019, 10, 1952–1957, doi:10.3762/bjnano.10.191

• to modify the crystallisation rate, which allows mesopores to form. In doing so, it also increases the disorder in the system, leading to agglomeration and different crystalline phases. Overall, we concluded that bare HP-SAPO-5 and MP-SAPO-5 systems were successfully synthesised. They were then used

Preservation of rutin nanosuspensions without the use of preservatives

• Pascal L. Stahr and
• Cornelia M. Keck

Beilstein J. Nanotechnol. 2019, 10, 1902–1913, doi:10.3762/bjnano.10.185

• changes the charge of the particles (zeta potential) and forces agglomeration of the nanocrystals. To avoid instabilities of nanosuspensions only very hydrophilic and non-charged preservatives, which will not interact with the nanocrystals, should be used. Due to the above-mentioned reasons, only a few

• thawing might also impair the physical stability of the nanocrystals and might cause agglomeration of the particles, which would then lead to a loss of the “nano properties”. Hence, in this case the method could not be exploited to preserve nanosuspensions without preservative. To investigate whether the

• PLX 188 yielded sizes of about 410 nm. Slightly larger nanocrystals with a slight agglomeration were obtained when Plantacare was used as stabilizer (Table 1 and Table 2). From this it was expected that non-preserved nanosuspensions stabilized with PLX 188 might possess a slightly better physical

Lipid nanostructures for antioxidant delivery: a comparative preformulation study

• Elisabetta Esposito,
• Maddalena Sguizzato,
• Markus Drechsler,
• Paolo Mariani,
• Federica Carducci,
• Claudio Nastruzzi,
• Giuseppe Valacchi and
• Rita Cortesi

Beilstein J. Nanotechnol. 2019, 10, 1789–1801, doi:10.3762/bjnano.10.174

• absent (Table 4). In addition, the extent of agglomeration was lower for NLC, probably due to the presence of the liquid lipid. Effect of lipid composition on nanoparticle size distribution The SLN and NLC dimensions, measured by PCS and expressed by the Z-average, Dz, are reported in Figure 1 and Table

• and concentration (Figure 1C and 1D). In order to avoid agglomeration phenomena and to control the mean size, only NLCs have been considered for antioxidant loading. Production and characterization of NLCs containing antioxidants To produce antioxidant-containing NLCs, different amounts of TOC and RA

• solubility to 4 mg/mL [48]. In the case of NLC T10-RA, despite the small mean diameter (98 nm), the agglomeration phenomenon was more noticeable as compared to NLC T10-TOC (Table 5). The NLC morphology was investigated by cryo-TEM and a few images are reported in Figure 2. In general, the NLC shape appears

Synthesis of nickel/gallium nanoalloys using a dual-source approach in 1-alkyl-3-methylimidazole ionic liquids

• Ilka Simon,
• Julius Hornung,
• Juri Barthel,
• Jörg Thomas,
• Maik Finze,
• Roland A. Fischer and
• Christoph Janiak

Beilstein J. Nanotechnol. 2019, 10, 1754–1767, doi:10.3762/bjnano.10.171

• agglomeration to allow for catalyst recycling over several runs [61]. To examine the influence of the ionic liquid, the reaction was repeated under solventless conditions with precipitated, largely IL-free NiGa nanoparticles. The NiGa nanoparticles were precipitated from the IL with acetonitrile and the IL was

Novel hollow titanium dioxide nanospheres with antimicrobial activity against resistant bacteria

• Carol López de Dicastillo,
• Cristian Patiño,
• María José Galotto,
• Yesseny Vásquez-Martínez,
• Claudia Torrent,
• Daniela Alburquenque,
• Alejandro Pereira and
• Juan Escrig

Beilstein J. Nanotechnol. 2019, 10, 1716–1725, doi:10.3762/bjnano.10.167

• inactivation of microorganisms due to its strong oxidizing power by free radical generation, such as hydroxyl and superoxide anion radicals [11][12]. Metal oxide NPs have been commonly synthesized by chemical and physical methods, which can produce a high size variability, defects and agglomeration and can

Layered double hydroxide/sepiolite hybrid nanoarchitectures for the controlled release of herbicides

• Ediana Paula Rebitski,
• Margarita Darder and
• Pilar Aranda

Beilstein J. Nanotechnol. 2019, 10, 1679–1690, doi:10.3762/bjnano.10.163

• -LDH/Sep0.5:1_150C material. This effect could be ascribed to a lower degree of agglomeration of the LDH particles grown on the sepiolite fibers in the nanoarchitecture with lower content in LDH, which may favor a faster ion exchange reaction. In fact, in MCPAie-LDH/Sep0.3:1_150C, in which the

Nanoporous smartPearls for dermal application – Identification of optimal silica types and a scalable production process as prerequisites for marketed products

• David Hespeler,
• Sanaa El Nomeiri,
• Jonas Kaltenbach and
• Rainer H. Müller

Beilstein J. Nanotechnol. 2019, 10, 1666–1678, doi:10.3762/bjnano.10.162

• nm, respectively), showed slight agglomeration. SP53D, having a medium-sized particle size of 12 µm, showed almost no agglomeration, and at a higher loading of 28% and 30%, a film formed on the wall of the evaporator glass. The XDP 3050 particles, having the largest diameter of 50 µm (pore diameter

• of 25 nm), showed neither agglomeration nor film formation. It is known that silica particles become more adhesive with decreasing size, which is easily explainable by powder technology. With decreasing particle size, the surface and contact area increase, thus promoting particle–particle interaction

• . Additionally, with increasing pore diameter, the agglomeration tendency decreases. The particles with a strong agglomeration tendency (AL-1 FP) have the smallest pore diameter of 3 nm, and additionally, the smallest pore volume. It is assumed that the pore parameters only play a significant role in

Development of a new hybrid approach combining AFM and SEM for the nanoparticle dimensional metrology

• Loïc Crouzier,
• Alexandra Delvallée,
• Sébastien Ducourtieux,
• Laurent Devoille,
• Guillaume Noircler,
• Christian Ulysse,
• Olivier Taché,
• Elodie Barruet,
• Christophe Tromas and
• Nicolas Feltin

Beilstein J. Nanotechnol. 2019, 10, 1523–1536, doi:10.3762/bjnano.10.150

• silicon substrates through the spin-coating method detailed in [11]. This method yields well-dispersed nanoparticles on the substrate while maximizing the number of isolated NPs preventing agglomeration of the NPs. NP SEM images have been recorded using a Zeiss ULTRA-Plus field-emission (FE) microscope

• , binarizing the image to discriminate objects from the substrate, identifying each imaged nano-object, evaluating roughness and building the size distribution histogram by only counting isolated nanoparticles. NP agglomeration may induce errors in the measurements and should be avoided [1][11]. The program is

BiOCl/TiO₂/diatomite composites with enhanced visible-light photocatalytic activity for the degradation of rhodamine B

• Minlin Ao,
• Kun Liu,
• Xuekun Tang,
• Zishun Li,
• Qian Peng and
• Jing Huang

Beilstein J. Nanotechnol. 2019, 10, 1412–1422, doi:10.3762/bjnano.10.139

• , low-cost and ease of application, which are superior to other approaches of environmental remediation [8][9]. However, the application of photocatalysis is still hindered due to the agglomeration of photocatalyst particles, the difficulty of photocatalyst recovery and low photocatalytic performance

• used to study the morphology of the samples. The BiOCl sample is composed of lamellar crystals with poor dispersity, presenting an agglomeration morphology (Figure 4a). The SEM results of pure TiO2 show that the poor dispersion of the TiO2 nanoparticles leads to agglomeration, as shown in Figure 4b

• . Figure 4c shows that diatomite in TiO2/diatomite maintains a disc morphology with many tiny TiO2 particles distributed on it without agglomeration. In the BTD composite (Figure 4d and 4e), the disc-like morphology of diatomite is still intact, and abundant and well-dispersed TiO2 nanoparticles and BiOCl

Highly ordered mesoporous silica film nanocomposites containing gold nanoparticles for the catalytic reduction of 4-nitrophenol

• Mohamad Azani Jalani,
• Leny Yuliati,
• Siew Ling Lee and
• Hendrik O. Lintang

Beilstein J. Nanotechnol. 2019, 10, 1368–1379, doi:10.3762/bjnano.10.135

• synthesis [21]. However, after template removal at 450 °C or above, both approaches suffer from agglomeration, non-homogenous distribution, and low insertion of AuNPs in the silicate nanochannels. On the other hand, hexagonal mesostructured silica nanomaterials with dense filling of organic functional

Alloyed Pt₃M (M = Co, Ni) nanoparticles supported on S- and N-doped carbon nanotubes for the oxygen reduction reaction

• Stéphane Louisia,
• Yohann R. J. Thomas,
• Pierre Lecante,
• Marie Heitzmann,
• M. Rosa Axet,
• Pierre-André Jacques and
• Philippe Serp

Beilstein J. Nanotechnol. 2019, 10, 1251–1269, doi:10.3762/bjnano.10.125

• fact, catalysts with small inter-particles distance with no agglomeration display excellent activity. Computational investigations have shown that decreasing the inter-particle distances causes an overlap of the electrochemical double layer. This overlap could reduce the oxide coverage of the NPs and

Photoactive nanoarchitectures based on clays incorporating TiO₂ and ZnO nanoparticles

• Eduardo Ruiz-Hitzky,
• Pilar Aranda,
• Marwa Akkari,
• Nithima Khaorapapong and
• Makoto Ogawa

Beilstein J. Nanotechnol. 2019, 10, 1140–1156, doi:10.3762/bjnano.10.114

• significant differences in size, degree of self-agglomeration as well as dispersion on the surface of the clay, which may influence the resulting properties of the materials. The principle of using the interfaces in layered clays is also applicable to fibrous clays with the generation of NPs homogeneously