Dokument: Quantitative Optical Studies Using Supported Lipid Bilayers - From Molecular Mobility to Collective Organization
| Titel: | Quantitative Optical Studies Using Supported Lipid Bilayers - From Molecular Mobility to Collective Organization | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=74315 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20260902-131520-6 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Coen, Luisa [Autor] | |||||||
| Dateien: |
| |||||||
| Beitragende: | Prof. Dr. Cornelia Monzel [Gutachter] Prof. Dr. Heinzel, Thomas [Gutachter] | |||||||
| Stichwörter: | Supported Lipid Bilayer, Superparamagnetic Biomembranes, Lateral Diffusion, CAR-NK cells, Immunological Synapse | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 530 Physik | |||||||
| Beschreibung: | Biological membranes constitute highly dynamic two-dimensional systems in which diffusion, intermolecular interactions, and external forces jointly determine molecular transport and spatial organization. While these processes are central to many cellular functions, their quantitative description remains challenging due to the complexity of biological environments. This work approaches this problem from a physical perspective by combining simplified model systems with advanced microscopy and quantitative image analysis.
Supported lipid bilayers are employed as controllable model membranes that retain essential features such as lateral fluidity while allowing systematic variation of experimental parameters. A central methodological aspect of this dissertation is the development and application of analysis strategies that convert fuorescence microscopy data into measurable quantities, including diffusion coefficients, molecular densities, transport velocities, and spatial organization metrics. To enable reproducible and scalable data analysis, dedicated image analysis software was developed. In this way, the work establishes a direct link between experimentally accessible imaging data and the underlying physical mechanisms governing membrane dynamics. The results demonstrate that membrane behavior can be consistently described in terms of a small set of quantitative observables. It is shown that the presence of mobile and immobile obstacles leads to pronounced deviations from ideal Brownian motion. These findings highlight the strong influence of spatial heterogeneity and confinement on transport processes in two-dimensional systems. By applying externally controllable forces mediated by magnetic nanoparticles, complex spatial patterns of biomolecules in and on membranes can be generated and stabilized in a controlled manner. This establishes a new experimental approach for magnetic molecular pattern formation and demonstrates for the first time that externally applied forces mediated by magnetic nanoparticles can be used to generate and stabilize complex molecular patterns of biomolecules in and on membranes, revealing how the interplay between intrinsic membrane properties and external driving forces can give rise to tunable non-equilibrium organization. The quantitative analysis of receptor organization at cellmembrane interfaces shows that complex molecular pattern formation emerges when cells adhere to biomimetic membrane interfaces. Using the medically relevant example of the immunological synapse, it is demonstrated that molecular phase separation and clustering within the adhesion zone are not only influenced by active cellular processes, but are also significantly shaped by passive molecular dynamics on the interacting cell and model membrane interfaces as well as by molecular concentration. This reflects collective behavior of biomolecules in the form of emergent, phase-separated organization. In this work, a detailed quantitative analysis of chimeric antigen receptor engineered natural killer cell synapse organization is presented, providing one of the first systematic insights into their structural organization at the nanoscale. In particular, spatial synapse formation and synapse size, rather than absolute receptor concentrations, are strongly influenced by externally defined ligand conditions. Furthermore, even non-signaling chimeric antigen receptors co-localize within the immunological synapse, indicating that receptor organization can arise from physical membrane processes independently of any cellular active process. Taken together, these results show that diffusion, active transport, and receptor organization can be understood as interconnected manifestations of membrane dynamics governed by physical principles. The work emphasizes that quantitative image analysis is essential for transforming microscopy from a descriptive tool into a method for extracting reproducible physical observables and for developing and testing theoretical models. By combining controlled model systems with rigorous data analysis, this dissertation contributes to a unified physical framework for describing transport and organization in two-dimensional and non-equilibrium membrane systems. | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Physik » Experimentalphysik | |||||||
| Dokument erstellt am: | 02.09.2026 | |||||||
| Dateien geändert am: | 02.09.2026 | |||||||
| Promotionsantrag am: | 24.06.2026 | |||||||
| Datum der Promotion: | 25.08.2026 |
