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1,159 results on '"Petri-Fink, Alke"'

106. A Near-Infrared Mechanically Switchable Elastomeric Film as a Dynamic Cell Culture Substrate.

Author

Spiaggia, Giovanni, Taladriz-Blanco, Patricia, Hengsberger, Stefan, Septiadi, Dedy, Geers, Christoph, Lee, Aaron, Rothen-Rutishauser, Barbara, and Petri-Fink, Alke

Subjects
CELL culture, GOLD nanoparticles, FOCAL adhesions, NANORODS, CELL membranes
Abstract

Commercial static cell culture substrates can usually not change their physical properties over time, resulting in a limited representation of the variation in biomechanical cues in vivo. To overcome this limitation, approaches incorporating gold nanoparticles to act as transducers to external stimuli have been employed. In this work, gold nanorods were embedded in an elastomeric matrix and used as photothermal transducers to fabricate biocompatible light-responsive substrates. The nanocomposite films analysed by lock-in thermography and nanoindentation show a homogeneous heat distribution and a greater stiffness when irradiated with NIR light. After irradiation, the initial stiffness values were recovered. In vitro experiments performed during NIR irradiation with NIH-3T3 fibroblasts demonstrated that these films were biocompatible and cells remained viable. Cells cultured on the light stiffened nanocomposite exhibited a greater proliferation rate and stronger focal adhesion clustering, indicating increased cell-surface binding strength. [ABSTRACT FROM AUTHOR]

Published
2023
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114. Particle size distribution measurements of manganese-doped ZnS nanoparticles

Author

Dieckmann, Yvonne, Colfen, Helmut, Hofmann, Heinrich, and Petri-Fink, Alke

Subjects
Manganese -- Properties, Manganese -- Usage, Zinc compounds -- Properties, Sulfides -- Properties, Nanoparticles -- Properties, Nanoparticles -- Composition, Semiconductor doping -- Research, Chemistry
Abstract

We performed particle size and particle size distribution measurements for L-cysteine-stabilized ZnS/Mn nanoparticles in the size region below 10 nm. For this we applied transmission electron microscopy (TEM), analytical ultracentrifugation (AUC), dynamic light scattering (DLS), and asymmetric flow field flow fractionation (aF-FFF) measurements, and we calculated particle sizes with the help of X-ray diffraction (XRD) patterns and the shift of the band gap absorption in the UV-vis spectrum. The different methods are explained, and their limitations are discussed, with the conclusion that only a combination of different techniques can yield a realistic and complete picture about the size distribution of the sample. From these methods TEM, AUC, DLS, and aF-FFF measure the actual particle size distribution either in dispersion or after drying of the sample, whereas the particle size obtained from XRD patterns and with the help of the band gap widening corresponds to the average size of the crystal domains within the particles. We obtained particle size distributions with their maximum between 3 and 7 nm and a mean crystallite size of 3.5-4 nm.

Published
2009

115. Particle Stiness and Surface Topography Determine Macrophage-Mediated Removal of Surface Adsorbed Particles

Author

Lee, Aaron, Septiadi, Dedy, Taladriz‐Blanco, Patricia, Almeida, Mauro, Haeni, Laetitia, Spuch‐Calvar, Miguel, Abdussalam, Wildan, Rothen‐Rutishauser, Barbara, and Petri‐Fink, Alke

Abstract

Cellular surface recognition and behavior are driven by a host of physical and chemical features which have been exploited to influence particle–cell interactions. Mechanical and topographical cues define the physical milieu which plays an important role in defining a range of cellular activities such as material recognition, adhesion, and migration through cytoskeletal organization and signaling. In order to elucidate the effect of local mechanical and topographical features generated by the adsorption of particles to an underlying surface on primary human monocyte‐derived macrophages (MDM), a series of poly(N‐isopropylacrylamide) (pNIPAM) particles with differing rigidity are self‐assembled to form a defined particle‐decorated surface. Assembly of particle‐decorated surfaces is facilitated by modification of the underlying glass to possess a positive charge through functionalization using 3‐aminopropyltriethoxysilane (APTES) or coating with poly(L‐lysine) (PLL). MDMs are noted to preferentially remove particles with higher degrees of crosslinking (stiffer) than those with lower degrees of crosslinking (softer). Alterations to the surface density of particles enabled a greater area of the particle‐decorated surface to be cleared. Uniquely, the impact of particle adsorption is evinced to have a direct impact on topographical recognition of the surface, suggesting a novel approach for controllably affecting cell‐surface recognition and response.

Published
2021

116. Versatile macroscale concentration gradients of nanoparticles in soft nanocomposites

Author

Taladriz‐Blanco, Patricia, Rothen‐Rutishauser, Barbara, Petri‐Fink, Alke, and Balog, Sandor

Abstract

Nanocomposite materials benefit from the diverse physicochemical properties featured by nanoparticles, and the presence of nanoparticle concentration gradients can lend functions to macroscopic materials beyond the realm of classical nanocomposites. It is shown here that linearity and time‐shift invariance obtained via the synergism of two independent physical phenomena—translational self‐diffusion and shear‐driven dispersion—may give access to an exceptionally high degree of flexibility in the design of scalable and programmable long‐range concentration gradients of nanoparticles in solidifiable liquid matrices.

Published
2020

118. Patient-derived and artificial ascites have minor effects on MeT-5A mesothelial cells and do not facilitate ovarian cancer cell adhesion

Author

Estermann, Manuela, Huang, Yen-Lin, Septiadi, Dedy, Ritz, Danilo, Liang, Ching-Yeu, Jacob, Francis, Drasler, Barbara, Petri-Fink, Alke, Heinzelmann-Schwarz, Viola, Rothen-Rutishauser, Barbara, Estermann, Manuela, Huang, Yen-Lin, Septiadi, Dedy, Ritz, Danilo, Liang, Ching-Yeu, Jacob, Francis, Drasler, Barbara, Petri-Fink, Alke, Heinzelmann-Schwarz, Viola, and Rothen-Rutishauser, Barbara

Abstract

The presence of ascites in the peritoneal cavity leads to morphological and functional changes of the peritoneal mesothelial cell layer. Cells loose cell-cell interactions, rearrange their cytoskeleton, activate the production of fibronectin, and change their cell surface morphology in a proinflammatory environment. Moreover, ovarian cancer cell adhesion has been shown to be facilitated by these changes due to increased integrin- and CD44-mediated binding sites. In this study, the biological responsiveness of the human pleural mesothelial cell line MeT-5A to patient-derived and artificial ascites was studied in vitro and adhesion of ovarian cancer cells, i.e. SKOV-3 cells, investigated. Changes were mainly observed in cells exposed to artificial ascites containing higher cytokine concentrations than patient-derived ascites. Interestingly, reduced cell-cell interactions were already observed in untreated MeT-5A cells and effects on tight junction protein expression and permeability upon exposure to ascites were minor. Ascites induced upregulation of CDC42 effector protein 2 expression, which affects stress fiber formation, however significant F-actin reorganization was not observed. Moreover, fibronectin production remained unchanged. Analysis of mesothelial cell surface characteristics showed upregulated expression of intercellular adhesion molecule 1, slightly increased hyaluronic acid secretion and decreased microvillus expression upon exposure to ascites. Nevertheless, the observed changes were not sufficient to facilitate adhesion of SKOV-3 cells on MeT-5A cell layer. This study revealed that MeT-5A cells show a reduced biological responsiveness to the presence of ascites, in contrast to published studies on primary human peritoneal mesothelial cells.

Published
2021

126. Understanding the Development, Standardization, and Validation Process of Alternative In Vitro Test Methods for Regulatory Approval from a Researcher Perspective

Author

Bas, Aurora, primary, Burns, Nicole, additional, Gulotta, Andrew, additional, Junker, James, additional, Drasler, Barbara, additional, Lehner, Roman, additional, Aicher, Lothar, additional, Constant, Samuel, additional, Petri‐Fink, Alke, additional, and Rothen‐Rutishauser, Barbara, additional

Published
2021
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133. Correction to Use of EpiAlveolar Lung Model to Predict Fibrotic Potential of Multiwalled Carbon Nanotubes

Author

Barosova, Hana, primary, Maione, Anna G., additional, Septiadi, Dedy, additional, Sharma, Monita, additional, Haeni, Laetitia, additional, Balog, Sandor, additional, O’Connell, Olivia, additional, Jackson, George R., additional, Brown, David, additional, Clippinger, Amy J., additional, Hayden, Patrick, additional, Petri-Fink, Alke, additional, Stone, Vicki, additional, and Rothen-Rutishauser, Barbara, additional

Published
2020
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134. Patient-derived and artificial ascites have minor effects on MeT-5A mesothelial cells and do not facilitate ovarian cancer cell adhesion

Author

Estermann, Manuela, primary, Huang, Yen-Lin, additional, Septiadi, Dedy, additional, Ritz, Danilo, additional, Liang, Ching-Yeu, additional, Jacob, Francis, additional, Drasler, Barbara, additional, Petri-Fink, Alke, additional, Heinzelmann-Schwarz, Viola, additional, and Rothen-Rutishauser, Barbara, additional

Published
2020
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140. Particle Surfaces to Study Macrophage Adherence, Migration, and Clearance

Author

Septiadi, Dedy, primary, Lee, Aaron, additional, Spuch‐Calvar, Miguel, additional, Moore, Thomas Lee, additional, Spiaggia, Giovanni, additional, Abdussalam, Wildan, additional, Rodriguez‐Lorenzo, Laura, additional, Taladriz‐Blanco, Patricia, additional, Rothen‐Rutishauser, Barbara, additional, and Petri‐Fink, Alke, additional

Published
2020
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145. Use of EpiAlveolar Lung Model to Predict Fibrotic Potential of Multiwalled Carbon Nanotubes

Author

Barosova, Hana, primary, Maione, Anna G., additional, Septiadi, Dedy, additional, Sharma, Monita, additional, Haeni, Laetitia, additional, Balog, Sandor, additional, O’Connell, Olivia, additional, Jackson, George R., additional, Brown, David, additional, Clippinger, Amy J., additional, Hayden, Patrick, additional, Petri-Fink, Alke, additional, Stone, Vicki, additional, and Rothen-Rutishauser, Barbara, additional

Published
2020
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148. Polydopamine nanoparticle doped nanofluid for solar thermal energy collector efficiency increase

Author

Hauser, Daniel, Steinmetz, Lukas, Balog, Sandor, Taladriz‐Blanco, Patricia, Septiadi, Dedy, Wilts, Bodo D., Petri‐Fink, Alke, and Rothen‐Rutishauser, Barbara

Abstract

Polydopamine can form black nanoparticles and has recently been gaining attention due to its extraordinary heating properties upon excitation with light. Herein, polydopamine hybrid nanoparticles are synthesized in different sizes and subsequently added to a solar fluid to analyze heating ability. The solar fluids with the differently sized hybrid polydopamine particles are compared to a solar fluid containing food coloring (i.e., micrometer‐sized soot particles, similar to India Ink) and silver nanoparticles. The hybrid polydopamine nanoparticles are found to heat more efficiently than silver nanoparticles or food coloring, respectively. In addition, no hybrid polydopamine nanoparticle deposits are found in the direct absorption solar collector in comparison to the solar fluids doped with silver nanoparticles or food coloring. Thus, this work shows that hybrid polydopamine nanoparticles are promising candidates to increase the efficiency of solar fluids.

Published
2020

149. Assessing meso- and microplastic pollution in the Ligurian and Tyrrhenian Seas

Author

Caldwell, Jessica, Petri-Fink, Alke, Rothen-Rutishauser, Barbara, and Lehner, Roman

Abstract

As the production of plastic products continues to increase, determining the fate of plastic waste in the environment is of high importance. Densely populated areas, such as Mediterranean coastlines, represent locations of high pollution risk for surrounding environments. Thus, this study aims to assess the abundance, size, and composition of floating meso- and microplastics collected during four weeks in 2018 in the Ligurian and Tyrrhenian Seas. The results show average meso- and microplastic particle concentrations of 28,376 ± 28,917 particles km−2, and an average mass of 268.61 ± 421.18 g km−2. The particle shape ratio was 65% fragments, 19% films, 10% lines, 4% foams, and 2% pellets. Microplastic particles comprised 65% of the sample. Analysis with attenuated total reflection Fourier transform infrared spectroscopy showed predominant polymer types included polyethylene, polypropylene, polystyrene, and polyamide. These data are an important starting point for long-term monitoring of plastic pollution levels within this region.

Published
2020

150. Particle Surfaces to Study Macrophage Adherence, Migration, and Clearance

Author

Septiadi, Dedy, Lee, Aaron, Spuch‐Calvar, Miguel, Moore, Thomas Lee, Spiaggia, Giovanni, Abdussalam, Wildan, Rodriguez‐Lorenzo, Laura, Taladriz‐Blanco, Patricia, Rothen‐Rutishauser, Barbara, and Petri‐Fink, Alke

Abstract

Nanoparticle adsorption to substrates pose a unique challenge to understand uptake mechanisms as it involves the organization of complex cytoskeletal components by cells to perform endocytosis/phagocytosis. In particular, it is not well‐understood from a cell mechanics perspective how the adhesion of particles on substrate will influence the ease of material clearance. By using a particle model, key contributing factors underlying cell adhesion on nonporous silica particle surfaces, migration and engulfment, are simulated and studied. Following a 24 h incubation period, monocyte‐ derived macrophages and A549 epithelial cells are able to adhere and remove particles in their local vicinity through induction of adhesive pulling arise from cell traction forces and phagocytic/endocytic mechanisms, in a size‐dependent manner. It is observed that such particle‐decorated surfaces can be used to address the influence of surface topography on cell behavior. Substrates which presented 480 nm silica particles are able to induce greater development and maturation of focal adhesions, which play an important role in cellular mechanoregulation. Moreover, under a chemotactic influence, in the presence of 30% fetal bovine serum, macrophages are able to uptake the particles and be directed to translocate along a concentration gradient, indicating that local mechanical effects do not substantially impair normal physiological functions.

Published
2020

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