Institut für Biophysik
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Item-typ:Veröffentlichung, Influence of Divalent Metal Ions on the Precipitation of the Plasma Protein Fibrinogen(American Chemical Society, 2021-10-20); ; ; ; Fibrinogen nanofibers are very attractive biomaterials to mimic the native blood clot architecture. Previously, we reported the self-assembly of fibrinogen nanofibers in the presence of monovalent salts and have now studied how divalent salts influence fibrinogen precipitation. Although the secondary fibrinogen structure was significantly altered with divalent metal ions, morphological analysis revealed exclusively smooth fibrinogen precipitates. In situ monitoring of the surface roughness facilitated predicting the tendency of various salts to form fibrinogen fibers or smooth films. Analysis of the chemical composition revealed that divalent salts were removed from smooth fibrinogen films upon rinsing while monovalent Na+ species were still present in fibrinogen fibers. Therefore, we assume that the decisive factor controlling the morphology of fibrinogen precipitates is direct ion–protein contact, which requires disruption of the ion-surrounding hydration shells. We conclude that in fibrinogen aggregates, this mechanism is effective only for monovalent ions, whereas divalent ions are limited to indirect fibrinogen adsorption.Wissenschaftlicher ArtikelBand:22Heft:1130 24 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Atomic force microscopy for cell mechanics and diseases(2020-04-22); ; ; Atomic Force Microscopy (AFM) is a powerful technique widely employed in biophysics, for instance to study topography of living cells and cell mechanics. Cell mechanics is a very interesting, biophysical parameter of cells, because it is strongly changed by various cellular processes, for example during cell division, cell movement, differentiation, aging, and also various diseases. Since cancer is a prominent example of changes in mechanical properties of diseases, the concept of the mechanical fingerprint has developed, which makes it possible to distinguish between healthy and diseased cells. In this article we report on various studies of cell mechanics with the AFM. We will first give a brief introduction on AFM principles and operational modes and then we will report on some applications of AFM in the field of cellular biophysics, like discriminating between healthy and cancer cells, as well as distinguishing cancer cells at different stages of malignancy. Overall, we will show that AFM has made a significant contribution in studying the biophysics of cancer and the concept of mechanical fingerprints could find a wide variety of applications in biomedicine and medical diagnostics.Wissenschaftlicher Artikel283 564 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Spatial patterning of nanofibrous collagen scaffolds modulates fibroblast morphology(IOP Publishing, 2021); ; ; ; Current knowledge about cell-biomaterial interactions is often based on two-dimensional (2D) cell culture systems like protein-coated glass slides. However, such smooth surfaces cannot mimic the nanofibrous environment of the native extracellular matrix (ECM). It is therefore a major challenge to transfer the results from 2D surfaces to 3D protein scaffolds with biomimetic nanofiber architecture. To understand the influence of different protein topographies on the cell response we introduce a new process to fabricate binary collagen scaffolds of variable thickness with spatially controlled regions of nanofibrous and smooth topography. We used pH-induced self-assembly to prepare collagen nanofibers with diameters between 130 and 150 nm on glass surfaces, which were partly covered with a polymer mask. After cross-linking with glutaraldehyde, smooth collagen films were prepared on the remaining glass regions. Atomic force microscopy revealed a much lower surface roughness of smooth collagen compared to nanofibers. Subsequently, we studied the viability, morphology and migration of 3T3 fibroblasts on both collagen topographies. We found small, elongated fibroblasts with few, long filopodia on collagen nanofibers whereas large, flat fibroblasts with many short filopodia were observed on smooth collagen. Actin stress fibers on collagen nanofibers were substantially reduced in comparison to smooth collagen. Live cell tracking revealed that fibroblasts on thin nanofibrous collagen migrated faster than on smooth collagen. In summary, binary collagen scaffolds enabled us for the first time to study cell responses to topographical cues on a single protein scaffold. In future, it will be intriguing to transfer our patterning process to other proteins to study fundamental principles of topography-dependent cell recognition processes.Wissenschaftlicher ArtikelBand:1360 62