TY - JOUR A1 - Kricheldorf, H.R. A1 - Rabenstein, M. A1 - Langanke, D. A1 - Schwarz, G. A1 - Schmidt, M. A1 - Maskos, M. A1 - Krüger, Ralph-Peter T1 - Ring-closing polycondensations N2 - The role of cyclization in polycondensations is discussed for two different scenarios: thermodynamically-controlled polycondensation (TCPs) on the one hand and kinetically-controlled polycondensations (KCPs) on the other. The classical Carothers–Flory theory of step-growth polymerization does not include cyclization reactions. However, TCPs involve the formation of cycles via ‘back-biting degradation’, and when the ring–chain equilibrium is on the side of the cycles the main reaction products of the TCP will be cyclic oligomers. Two groups of examples are discussed: polycondensations of salicyclic acid derivatives (e.g. aspirin) and polycondensations of dibutyltin derivatives with long {alpha}-, {omega}-diols or dicarboxylic acids. Furthermore, various kinetically-controlled syntheses of polyesters and polyamides were studied and carefully optimized in the direction of high molecular weights. High fractions of cyclic oligomers and polymers were found by MALDI-TOF mass spectrometry, and their fractions increased with optimization of the process for molecular weight. These results disagree with the Carothers–Flory theory but agree with the theoretical background of the Ruggli–Ziegler dilution method (RZDM). When poly(ether-sulfone)s were prepared from 4,4'-difluorodiphenylsulfone and silylated bisphenol-A two different scenarios were found. With CsF as catalyst at a temperature of more than 145°C cyclic oligoethers were formed under thermodynamic control. When the polycondensation was promoted with K2CO3 in N-methylpyrolidone at ?145°C the formation of cyclic oligoethers and polyethers occurred under kinetic control. A new mathematical formula is presented correlating the average degree of polymerization with the conversion and taking into account the competition between cyclization and propagation. PY - 2001 DO - https://doi.org/10.1088/0954-0083/13/2/312 SN - 0954-0083 SN - 1361-6412 VL - 13 SP - S123 EP - S136 PB - Sage Publ. CY - London AN - OPUS4-2178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Luty-Blocho, M. A1 - Fitzner, K. A1 - Hessel, V. A1 - Löb, P. A1 - Maskos, Michael A1 - Metzke, D. A1 - Paclawski, K. A1 - Wojnicki, M. T1 - Synthesis of gold nanoparticles in an interdigital micromixer using ascorbic acid and sodium borohydride as reducers N2 - Continuous-flow process conditions for the reduction to gold nanoparticles were varied following a variation scheme aiming at impacting each of the elementary steps–mixing, reaction, polymer diffusion and polymer binding. While the last three variations are done by proper material choice (reducer; polymeric stabilizer), flow processing using a multilamination micromixer intensified the mass transfer in all these steps and particularly improved the first mixing step of the reactants. As reducers L-ascorbic acid (H2Asc) and sodium borohydride (NaBH4) were used and as gold particle precursor chloroauric acid (HAuCl4). All processing runs were analysed by plasmon absorption and transmission electron microscopy to reveal size, shape and polydispersity. For the HAuCl4-H2Asc system, the smallest particles were 0.8–4 nm (7.5 mL/min) and 0.6–3 nm (10.0 mL/min) for the HAuCl4-NaBH4 system. This is at the upper edge of performance reported for batch systems in literature, i.e. among the smallest gold particles generated. While the particles made for the HAuCl4-H2Asc system were polydisperse and polyshaped for most process conditions (however being spherical and relatively uniform at the two largest flow rates investigated), processing with the HAuCl4-NaBH4 system resulted in particles sizes with small mean deviation and almost ideal spherical shape. With polyvinyl alcohol (PVA) as stabilizer, stable colloids were obtained for one week (violet coloured) up to at least 2 months (pink coloured) in case of reaction with ascorbic acid, and for at least 1 month in case of reaction with NaBH4. KW - Au nanoparticles KW - Kinetic of reduction reaction KW - Micromixer KW - Plasmon resonance PY - 2011 DO - https://doi.org/10.1016/j.cej.2011.03.104 SN - 1385-8947 SN - 0300-9467 SN - 0923-0467 SN - 0009-2487 VL - 171 IS - 1 SP - 279 EP - 290 PB - Elsevier CY - Amsterdam ; Boston, Mass. ; Jena ; London ; New York, NY ; Oxford ; Paris ; Philadelphia, PA ; San Diego, Calif. ; St. Louis, Mo. AN - OPUS4-25423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lüdicke, M. G. A1 - Hildebrandt, Jana A1 - Schindler, C. A1 - Sperling, R. A. A1 - Maskos, M. T1 - Automated QuantumDots Purification via Solid Phase Extraction N2 - The separation of colloidal nanocrystals from their original synthesis medium is an essential process step towards their application, however, the costs on a preparative scale are still a constraint. A new combination of approaches for the purification of hydrophobic Quantum Dots is presented, resulting in an efficient scalable process in regard to time and solvent consumption, using common laboratory equipment and low-cost materials. The procedure is based on a combination of solvent-induced adhesion and solid phase extraction. The platform allows the transition from manual handling towards automation, yielding an overall purification performance similar to one conventional batch precipitation/centrifugation step, which was investigated by thermogravimetry and gas chromatography. The distinct miscibility gaps between surfactants used as nanoparticle capping agents, original and extraction medium are clarified by their phase diagrams, which confirmed the outcome of the flow chemistry process. Furthermore, the solubility behavior of the Quantum Dots is put into context with the Hansen solubility parameters framework to reasonably decide upon appropriate solvent types. KW - Quantum Dots KW - Purification PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559590 DO - https://doi.org/10.3390/nano12121983 SN - 2079-4991 VL - 12 IS - 12 PB - MDPI CY - Basel AN - OPUS4-55959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koshkina, Olga A1 - Westmeier, D. A1 - Lang, Thomas A1 - Bantz, C. A1 - Hahlbrock, A. A1 - Würth, Christian A1 - Resch-Genger, Ute A1 - Braun, Ulrike A1 - Thiermann, Raphael A1 - Weise, C. A1 - Eravci, M. A1 - Mohr, B. A1 - Schlaad, H. A1 - Stauber, R. H. A1 - Docter, D. A1 - Bertin, Annabelle A1 - Maskos, M. T1 - Tuning the surface of nanoparticles: Impact of poly(2-ethyl-2-oxazoline) on protein adsorption in serum and cellular uptake N2 - Due to the adsorption of biomolecules, the control of the biodistribution of nanoparticles is still one of the major challenges of nanomedicine. Poly(2-ethyl-2-oxazoline) (PEtOx) for surface modification of nanoparticles is applied and both protein adsorption and cellular uptake of PEtOxylated nanoparticles versus nanoparticles coated with poly(ethylene glycol) (PEG) and non-coated positively and negatively charged nanoparticles are compared. Therefore, fluorescent poly(organosiloxane) nanoparticles of 15 nm radius are synthesized, which are used as a scaffold for surface modification in a grafting onto approach. With multi-angle dynamic light scattering, asymmetrical flow field-flow fractionation, gel electrophoresis, and liquid chromatography-mass spectrometry, it is demonstrated that protein adsorption on PEtOxylated nanoparticles is extremely low, similar as on PEGylated nanoparticles. Moreover, quantitative microscopy reveals that PEtOxylation significantly reduces the non-specific cellular uptake, particularly by macrophage-like cells. Collectively, studies demonstrate that PEtOx is a very effective alternative to PEG for stealth modification of the surface of nanoparticles. KW - Poloxazolines KW - Protein corona KW - Cellular uptake PY - 2016 DO - https://doi.org/10.1002/mabi.201600074 SN - 1616-5187 SN - 1616-5195 VL - 16 IS - 9 SP - 1287 EP - 1300 AN - OPUS4-37369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bleul, Regina A1 - Thiermann, R. A1 - Marten, G.U. A1 - House, M.J. A1 - St. Pierre, T.G. A1 - Häfeli, U.O. A1 - Maskos, M. T1 - Continuously manufactured magnetic polymersomes - a versatile tool (not only) for targeted cancer therapy N2 - Micromixer technology was used to prepare polymeric vesicles (Pluronic® L-121) dual loaded with the anti-cancer drug camptothecin and magnetic nanoparticles. Successful incorporation of the magnetic nanoparticles was confirmed by transmission electron microscopy. Dynamic light scattering measurements showed a relatively narrow size distribution of the hybrid polymersomes. Camptothecin polymersomes reduced the cell viability of prostate cancer cells (PC-3) measured after 72 h significantly, while drug-free polymersomes showed no cytotoxic effects. Covalent attachment of a cancer targeting peptide (bombesin) as well as a fluorescent label (Alexa Fluor® 647) to the hybrid polymersomes was performed and specific cell binding and internalization were shown by flow cytometry and confocal microscopy. Relaxometry measurements clearly demonstrated the capacity of magnetic polymersomes to generate significant T2-weighted MRI contrast and potentially allow for direct monitoring of the biodistribution of the polymersomes. Micromixer technology as an easy, fast and efficient way to manufacture hybrid polymersomes as theranostic drug delivery devices is a further step from basic research to personalized medicine. KW - Polymersomes KW - Pluronics KW - Drug delivery KW - Theranostics KW - Micro mixer PY - 2013 DO - https://doi.org/10.1039/c3nr02190d SN - 2040-3364 SN - 2040-3372 SP - 1 EP - 9(?) PB - RSC Publ. CY - Cambridge AN - OPUS4-28847 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dwivedi, M.V. A1 - Harishchandra, R.K. A1 - Koshkina, Olga A1 - Maskos, M. A1 - Galla, H.-J. T1 - Size influences the effect of hydrophobic nanoparticles on lung surfactant model systems N2 - The alveolar lung surfactant (LS) is a complex lipid protein mixture that forms an interfacial monolayer reducing the surface tension to near zero values and thus preventing the lungs from collapse. Due to the expanding field of nanotechnology and the corresponding unavoidable exposure of human beings from the air, it is crucial to study the potential effects of nanoparticles (NPs) on the structural organization of the lung surfactant system. In the present study, we investigated both, the domain structure in pure DPPC monolayers as well as in lung surfactant model systems. In the pure lipid system we found that two different sized hydrophobic polymeric nanoparticles with diameter of ~12 nm and ~136 nm have contrasting effect on the functional and structural behavior. The small nanoparticles inserted into fluid domains at the LE-LC phase transition are not visibly disturbing the phase transition but disrupting the domain morphology of the LE phase. The large nanoparticles led to an expanded isotherm and to a significant decrease in the line tension and thus to a drastic disruption of the domain structures at a much lower number of nanoparticles with respect to the lipid. The surface activity of the model LS films again showed drastic variations due to presence of different sized NPs illustrated by the film balance isotherms and the atomic force microscopy. AFM revealed laterally profuse multilayer protrusion formation on compression but only in the presence of 136 nm sized nanoparticles. Moreover we investigated the vesicle insertion process into a preformed monolayer. A severe inhibition was observed only in the presence of ~136 nm NPs compared to minor effects in the presence of ~12 nm NPs. Our study clearly shows that the size of the nanoparticles made of the same material determines the interaction with biological membranes. KW - Lung surfactant KW - Nanoparticle size KW - Surface activity KW - Atomic force microscopy KW - Vesicle insertion kinetics KW - Multilayer protrusion structures PY - 2014 DO - https://doi.org/10.1016/j.bpj.2013.10.036 SN - 0006-3495 SN - 1542-0086 VL - 106 IS - 1 SP - 289 EP - 298 PB - Biophysical Society CY - Bethesda, Md. AN - OPUS4-30519 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bleul, Regina A1 - Thiermann, Raphael A1 - Saatchi, K. A1 - Häfeli, U.O. A1 - Maskos, M. ED - Parak, W.J. ED - Osinski, M. ED - Yamamoto, K. T1 - Multifunctional nanocarriers for biomedical applications N2 - Polymeric vesicles (Pluronic® L-121) loaded with magnetic nanoparticles (MNP) and an anti-cancer drug (camptothecin) were prepared continuously in a micro mixing device. Characterization by TEM confirmed the successful incorporation of the MNP and DLS measurements showed a relatively narrow size distribution of the hybrid polymersomes. A very high drug loading of camptothecin (100 µg/ml in the polymersome formulation) was reached and a drug release study of loaded magnetic polymersomes has shown a sustained camptothecin release over several days. Carboxylation of Pluronic® L-121 was performed and enabled a further surface functionalization with bombesin, a 14 amino acid peptide, which binds specifically to the GRPR (gastrin releasing peptide receptor). This receptor is often overexpressed in tumor cells (e.g., human prostate cancer cells) and therefore a suitable target for cancer treatment. An additional fluorescence label with Alexa Fluor® 647 allow tracking of the polymersomes e.g., in cell experiments. Relaxivity measurements to evaluate the potential of magnetic polymersomes as MR contrast agent for in vivo imaging are in progress. T2 - Colloidal nanocrystals for biomedical applications VIII CY - San Francisco, CA, USA DA - 2013-02-22 KW - Polymersomes KW - Vesicles KW - Block copolymers KW - Pluronics KW - Drug delivery KW - Micro mixer PY - 2013 SN - 9780819493644 DO - https://doi.org/10.1117/12.2008194 N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 8595 SP - 85951N-1 - 85951N-9 AN - OPUS4-28488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kasper, J. A1 - Hermanns, M. A1 - Bantz, C. A1 - Maskos, Michael A1 - Stauber, R. A1 - Pohl, C. A1 - Unger, R. E. A1 - Kirkpatrick, J.C. T1 - Inflammatory and cytotoxic responses of an alveolar-capillary coculture model to silica nanoparticles: comparison with conventional monocultures N2 - To date silica nanoparticles (SNPs) play an important role in modern technology and nanomedicine. SNPs are present in various materials (tyres, electrical and thermal insulation material, photovoltaic facilities). They are also used in products that are directly exposed to humans such as cosmetics or toothpaste. For that reason it is of great concern to evaluate the possible hazards of these engineered particles for human health. Attention should primarily be focussed on SNP effects on biological barriers. Accidentally released SNP could, for example, encounter the alveolar-capillary barrier by inhalation. In this study we examined the inflammatory and cytotoxic responses of monodisperse amorphous silica nanoparticles (aSNPs) of 30 nm in size on an in vitro coculture model mimicking the alveolar-capillary barrier and compared these to conventional monocultures. Methods Thus, the epithelial cell line, H441, and the endothelial cell line, ISO-HAS-1, were used in monoculture and in coculture on opposite sides of a filter membrane. Cytotoxicity was evaluated by the MTS assay, detection of membrane integrity (LDH release), and TER (Transepithelial Electrical Resistance) measurement. Additionally, parameters of inflammation (sICAM-1, IL-6 and IL-8 release) and apoptosis markers were investigated. Results Regarding toxic effects (viability, membrane integrity, TER) the coculture model was less sensitive to apical aSNP exposure than the conventional monocultures of the appropriate cells. On the other hand, the in vitro coculture model responded with the release of inflammatory markers in a much more sensitive fashion than the conventional monoculture. At concentrations that were 10-100fold less than the toxic concentrations the apically exposed coculture showed a release of IL-6 and IL-8 to the basolateral side. This may mimic the early inflammatory events that take place in the pulmonary alveoli after aSNP inhalation. Furthermore, a number of apoptosis markers belonging to the intrinsic pathway were upregulated in the coculture following aSNP treatment. Analysis of the individual markers indicated that the cells suffered from DNA damage, hypoxia and ER-stress. Conclusion We present evidence that our in vitro coculture model of the alveolar-capillary barrier is clearly advantageous compared to conventional monocultures in evaluating the extent of damage caused by hazardous material encountering the principle biological barrier in the lower respiratory tract. KW - Silica nanoparticles KW - Alveolar-capillary coculture model KW - Cytotoxicity PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-254217 DO - https://doi.org/10.1186/1743-8977-8-6 SN - 1743-8977 VL - 8 IS - 6 SP - 1 EP - 16(?) PB - BioMed Central CY - London AN - OPUS4-25421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kocun, M. A1 - Mueller, W. A1 - Maskos, Michael A1 - Mey, I. A1 - Geil, B. A1 - Steinem, C. A1 - Janshoff, A. T1 - Viscoelasticity of pore-spanning polymer membranes derived from giant polymersomes N2 - We show how the viscoelastic properties of membranes formed from poly(butadiene)-block-poly(ethylene oxide) (PB130-b-PEO66) block copolymers can be locally accessed by atomic force microscopy. Polymer membranes are spread on microstructured porous silicon substrates from PB130-b-PEO66 vesicles by decreasing the osmotic pressure of the solution. Local viscoelastic properties of the pore-spanning polymer membranes were obtained from site-specific indentation experiments. Elastic moduli of these membranes were in the order of few MPa, while the elastic moduli of cross-linked membranes considerably increased to few GPa. Furthermore, the energy dissipation and velocity dependence of the hysteresis between indentation and relaxation were quantified and compared with a modified Kelvin-Voigt model. Relaxation times were in the order of hundreds of milliseconds explaining why the stiffness of the membrane increases with increasing indentation velocity. PY - 2010 DO - https://doi.org/10.1039/b924650a SN - 1744-683X VL - 6 SP - 2508 EP - 2516 PB - RSC Publ. CY - Cambridge AN - OPUS4-21553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scherer, Christian A1 - Noskov, S. A1 - Utech, S. A1 - Bantz, C. A1 - Mueller, W. A1 - Krohne, K. A1 - Maskos, M. T1 - Characterization of polymer nanoparticles by asymmetrical flow field flow fractionation (AF-FFF) KW - Nanoparticles KW - Block copolymersm maghemite KW - Core-shell structure KW - Polyorganosiloxane PY - 2010 DO - https://doi.org/10.1166/jnn.2010.2973 SN - 1533-4880 VL - 10 IS - 10 SP - 6834 EP - 6839 PB - American Scientific Publ. CY - Stevenson Ranch, Calif., USA AN - OPUS4-21979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krohne, Korinna A1 - Duschner, S. A1 - Störkle, D. A1 - Schmidt, M. A1 - Maskos, Michael T1 - Topologically controlled inter-polyelectrolyte complexes between molecular bottlebrushes and dendrimers N2 - The complexation of a cylindrical polyelectrolyte–brush-surfactant complex (PMMPSS–C12) and an oppositely charged generation-5 PAMAM dendrimer (G5-PAMAM) in methanol (MeOH) leads to kinetically controlled formation of interpolyelectrolyte complexes. In contrast, the complexation of the same starting materials in solvents with higher dielectric constant such as dimethylformamide (DMF) or N-methylformamide (NMF) results in the formation of topologically controlled complexes of cylindrical morphology. The composition of the complexes is analyzed by static and dynamic light scattering (SLS, DLS) in solution and atomic force microscopy (AFM) after spin-casting the complexes onto mica. The analyzed complexes seem to consist of one PMMPSS–C12 molecule and, with increasing G5-PAMAM content, of an increasing number of G5-PAMAM dendrimers. KW - Macromolecules PY - 2010 DO - https://doi.org/10.1021/ma101630h SN - 0024-9297 SN - 1520-5835 VL - 43 IS - 20 SP - 8645 EP - 8650 PB - American Chemical Society CY - Washington, DC AN - OPUS4-22447 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koshkina, Olga A1 - Lang, Thomas A1 - Thiermann, R. A1 - Docter, D. A1 - Stauber, R.H. A1 - Secker, C. A1 - Schlaad, H. A1 - Weidner, Steffen A1 - Mohr, B. A1 - Maskos, M. A1 - Bertin, Annabelle T1 - Temperature-triggered protein adsorption on polymer-coated nanoparticles in serum N2 - The protein corona, which forms on the nanoparticle's surface in most biological media, determines the nanoparticle’s physicochemical characteristics. The formation of the protein corona has a significant impact on the biodistribution and clearance of nanoparticles in vivo. Therefore, the ability to influence the formation of the protein corona is essential to most biomedical applications, including drug delivery and imaging. In this study, we investigate the protein adsorption on nanoparticles with a hydrodynamic radius of 30 nm and a coating of thermoresponsive poly(2-isopropyl-2-oxazoline) in serum. Using multiangle dynamic light scattering (DLS) we demonstrate that heating of the nanoparticles above their phase separation temperature induces the formation of agglomerates, with a hydrodynamic radius of 1 µm. In serum, noticeably stronger agglomeration occurs at lower temperatures compared to serum-free conditions. Cryogenic transmission electron microscopy (cryo-TEM) revealed a high packing density of agglomerates when serum was not present. In contrast, in the presence of serum, agglomerated nanoparticles were loosely packed, indicating that proteins are intercalated between them. Moreover, an increase in protein content is observed upon heating, confirming that protein adsorption is induced by the alteration of the surface during phase separation. After cooling and switching the surface back, most of the agglomerates were dissolved and the main fraction returned to the original size of approximately 30 nm as shown by asymmetrical flow-field flow fractionation (AF-FFF) and DLS. Furthermore, the amounts of adsorbed proteins are similar before and after heating the nanoparticles to above their phase-separation temperature. Overall, our results demonstrate that the thermoresponsivity of the polymer coating enables turning the corona formation on nanoparticles on and off in situ. As the local heating of body areas can be easily done in vivo, the thermoresponsive coating could potentially be used to induce the agglomeration of nanoparticles and proteins and the accumulation of nanoparticles in a targeted body region. PY - 2015 DO - https://doi.org/10.1021/acs.langmuir.5b00537 SN - 0743-7463 SN - 1520-5827 VL - 31 IS - 32 SP - 8873 EP - 8881 PB - American Chemical Society CY - Washington, DC AN - OPUS4-34163 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bantz, C. A1 - Koshkina, Olga A1 - Lang, Thomas A1 - Galla, H.-J. A1 - Kirkpatrick, C.J. A1 - Stauber, R.H. A1 - Maskos, M. T1 - The surface properties of nanoparticles determine the agglomeration state and the size of the particles under physiological conditions N2 - Due to the recent widespread application of nanomaterials to biological systems, a careful consideration of their physiological impact is required. This demands an understanding of the complex processes at the bio–nano interface. Therefore, a comprehensive and accurate characterization of the material under physiological conditions is crucial to correlate the observed biological impact with defined colloidal properties. As promising candidates for biomedical applications, two SiO2-based nanomaterial systems were chosen for extensive size characterization to investigate the agglomeration behavior under physiological conditions. To combine the benefits of different characterization techniques and to compensate for their respective drawbacks, transmission electron microscopy, dynamic light scattering and asymmetric flow field-flow fractionation were applied. The investigated particle systems were (i) negatively charged silica particles and (ii) poly(organosiloxane) particles offering variable surface modification opportunities (positively charged, polymer coated). It is shown that the surface properties primarily determine the agglomeration state of the particles and therefore their effective size, especially under physiological conditions. Thus, the biological identity of a nanomaterial is clearly influenced by differentiating surface properties. KW - Nanomaterial characterization KW - Physiological conditions KW - Surface properties KW - Silica nanoparticles KW - Siloxane nanoparticles KW - Nanoparticles KW - Colloids KW - Silica KW - Polyorganosiloxane KW - Siloxane KW - Characterization KW - Transmission electron microscopy KW - TEM KW - Cryo-TEM KW - Asymetrical flow field-flow fractionation KW - AF-FFF KW - Field-flow fractionation KW - FFF KW - Dynamic light scattering KW - DLS KW - PCS PY - 2014 DO - https://doi.org/10.3762/bjnano.5.188 SN - 2190-4286 VL - 5 SP - 1774 EP - 1786 CY - Frankfurt, M. AN - OPUS4-32575 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Orts Gil, Guillermo A1 - Natte, Kishore A1 - Thiermann, Raphael A1 - Girod, Matthias A1 - Rades, Steffi A1 - Kalbe, Henryk A1 - Thünemann, Andreas A1 - Maskos, M. A1 - Österle, Werner T1 - On the role of surface composition and curvature on biointerface formation and colloidal stability of nanoparticles in a protein-rich model system N2 - The need for a better understanding of nanoparticle–protein interactions and the mechanisms governing the resulting colloidal stability has been emphasised in recent years. In the present contribution, the short and long term colloidal stability of silica nanoparticles (SNPs) and silica–poly(ethylene glycol) nanohybrids (Sil–PEG) have been scrutinised in a protein model system. Well-defined silica nanoparticles are rapidly covered by bovine serum albumin (BSA) and form small clusters after 20 min while large agglomerates are detected after 10 h depending on both particle size and nanoparticle–protein ratio. Oppositely, Sil–PEG hybrids present suppressive protein adsorption and enhanced short and long term colloidal stability in protein solution. No critical agglomeration was found for either system in the absence of protein, proving that instability found for SNPs must arise as a consequence of protein adsorption and not to high ionic environment. Analysis of the small angle X-ray scattering (SAXS) structure factor indicates a short-range attractive potential between particles in the silica-BSA system, which is in good agreement with a protein bridging agglomeration mechanism. The results presented here point out the importance of the nanoparticle surface properties on the ability to adsorb proteins and how the induced or depressed adsorption may potentially drive the resulting colloidal stability. KW - Nanoparticles KW - Protein corona KW - Biointerface KW - BSA KW - PEG KW - Colloidal stability PY - 2013 DO - https://doi.org/10.1016/j.colsurfb.2013.02.027 SN - 0927-7765 SN - 1873-4367 VL - 108 SP - 110 EP - 119 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-30100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kasper, J. A1 - Hermanns, M.I. A1 - Bantz, C. A1 - Koshkina, Olga A1 - Lang, Thomas A1 - Maskos, Michael A1 - Pohl, C. A1 - Unger, R. E. A1 - Kirkpatrick, C.J. T1 - Interactions of silica nanoparticles with lung epithelial cells and the association to flotillins N2 - Amorphous silica nanoparticles (aSNPs) gain increasing popularity for industrial and therapeutic claims. The lung with its surface area of 1006#8211;140 m² displays an ideal target for therapeutic approaches, but it represents also a serious area of attack for harmful nanomaterials. The exact nature of the cytotoxic effects of NPs is still unknown. Furthermore, cellular pathways and the destiny of internalized NPs are still poorly understood. Therefore, we examined the cytotoxicity (MTS, LDH) and inflammatory responses (IL-8) for different-sized aSNPs (30, 70, 300 nm) on our lung epithelial cells line NCI H441 and endothelial cell line ISO-HAS-1. Additionally, colocalization studies have been conducted via immunofluorescence staining for flotillin-1- and flotillin-2-bearing endocytic vesicles. Subsequently, the relevance of flotillins concerning the viability of aSNP-exposed epithelial cells has been evaluated using flotillin-1/2 depleted cells (siRNA). This study reveals the relevance of the nanoparticle size regarding cytotoxicity (MTS, LDH) and inflammatory responses (IL-8), whereat the smaller the size of the nanoparticle is, the more harmful are the effects. All different aSNP sizes have been incorporated in flotillin-1- and flotillin-2-labelled vesicles in lung epithelial and endothelial cells, which display a marker for late endosomal or lysosomal structures and appear to exhibit a clathrin- or caveolae-independent mode of endocytosis. Flotillin-depleted H441 showed a clearly decreased uptake of aSNPs. Additionally, the viability of aSNP-exposed cells was reduced in these cells. These findings indicate a contribution of flotillins in as yet unknown (clathrin or caveolae-independent) endocytosis mechanisms and (or) endosomal storage. KW - Silica nanoparticles KW - Alveolar-capillary barrier KW - Lung epithelial cells KW - Endothelial cells KW - Endocytosis KW - Flotillin-1 KW - Flotillin-2 KW - Cytotoxicity KW - Inflammatory response PY - 2012 UR - http://link.springer.com/content/pdf/10.1007%2Fs00204-012-0876-5 DO - https://doi.org/10.1007/s00204-012-0876-5 SN - 0340-5761 SN - 1432-0738 SP - 1 EP - 13(?) PB - Springer CY - Berlin ; Heidelberg [u.a.] AN - OPUS4-26195 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kasper, J. A1 - Herrmanns, M.I. A1 - Bantz, C. A1 - Utech, S. A1 - Koshkina, Olga A1 - Maskos, Michael A1 - Brochhausen, C. A1 - Pohl, C. A1 - Fuchs, S. A1 - Unger, R. E. A1 - Kirkpatrick, C.J. T1 - Flotillin-involved uptake of silica nanoparticles and responses of an alveolar-capillary barrier in vitro N2 - Drug and gene delivery via nanoparticles across biological barriers such as the alveolar-capillary barrier of the lung constitutes an interesting and increasingly relevant field in nanomedicine. Nevertheless, potential hazardous effects of nanoparticles (NPs) as well as their cellular and systemic fate should be thoroughly examined. Hence, this study was designed to evaluate the effects of amorphous silica NPs (Sicastar) and (poly)organosiloxane NPs (AmOrSil) on the viability and the inflammatory response as well as on the cellular uptake mechanisms and fate in cells of the alveolar barrier. For this purpose, the alveolar epithelial cell line (NCI H441) and microvascular endothelial cell line (ISO-HAS-1) were used in an experimental set up resembling the alveolar-capillary barrier of the lung. In terms of IL-8 and sICAM Sicastar resulted in harmful effects at higher concentrations (60 µg/ml) in conventional monocultures but not in the coculture, whereas AmOrSil showed no significant effects. Immunofluorescence counterstaining of endosomal structures in NP-incubated cells showed no evidence for a clathrin- or caveolae-mediated uptake mechanism. However, NPs were enclosed in flotillin-1 and -2 marked vesicles in both cell types. Flotillins appear to play a role in cellular uptake or trafficking mechanisms of NPs and are discussed as indicators for clathrin- or caveolae-independent uptake mechanisms. In addition, we examined the transport of NPs across this in vitro model of the alveolar-capillary barrier forming a tight barrier with a transepithelial electrical resistance of 560 ± 8 Ω cm². H441 in coculture with endothelial cells took up much less NPs compared to monocultures. Moreover, coculturing prevented the transport of NP from the epithelial compartment to the endothelial layer on the bottom of the filter insert. This supports the relevance of coculture models, which favour a differentiated and polarised epithelial layer as in vitro test systems for nanoparticle uptake. KW - Silica nanoparticles KW - Alveolar-capillary barrier KW - NP uptake KW - NP-transport KW - Endocytosis KW - Flotillin-1/-2-dependent uptake/trafficking PY - 2013 DO - https://doi.org/10.1016/j.ejpb.2012.10.011 SN - 0939-6411 SN - 1873-3441 VL - 84 IS - 2 SP - 275 EP - 287 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-28841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -