Atomic force microscopy to elucidate lipid membranes enhanced by engineered liposomes
[eng] The research in this thesis aimed to study and generate an engineered formulation that can fuse with cell membranes and carry drugs or other compounds into cells. HeLa cells were chosen as the target cells and prior to their use, a model membrane mimicking the lipid membrane of HeLa cells was...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2022 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/187522 |
| Acceso en línea: | https://hdl.handle.net/2445/187522 http://hdl.handle.net/10803/674746 |
| Access Level: | acceso abierto |
| Palabra clave: | Nanomedicina Microscòpia de força atòmica Membranes cel·lulars Liposomes Nanomedicine Atomic force microscopy Cell membranes |
| Sumario: | [eng] The research in this thesis aimed to study and generate an engineered formulation that can fuse with cell membranes and carry drugs or other compounds into cells. HeLa cells were chosen as the target cells and prior to their use, a model membrane mimicking the lipid membrane of HeLa cells was developed. Starting from the basic components and using a bottom-up approach, different phospholipids were studied and compared to identify the construction blocks of liposomes and assess the effects of cholesterol on these phospholipids. After selecting the desired composition, a membrane model mimicking the HeLa cell membrane was developed to test its fusion with the engineered liposomes and to understand the fusion process before starting in vitro assays with living HeLa cells. In the in vitro assays, the engineered liposomes were able to fuse with the cell membrane as well as carry and liberate a model drug (methotrexate) into the cells, demonstrating that the engineered liposomes can work efficiently as nanocarriers. Across the entire thesis, one technique was constantly used, atomic force microscopy (AFM). This technique enables the study of the smallest samples, such as lipid monolayers, as well as larger samples, like HeLa cells. AFM can also be used to obtain the physicochemical properties of samples using the force spectroscopy mode, allowing the analysis of samples and providing insight into the nanomechanics of the samples studied. Several techniques were used in this thesis, including the application of a Langmuir-Blodgett trough to study the physicochemical properties of lipids, fluorescence resonance energy transfer (FRET) to determine the fusion of the engineered liposomes, visualization techniques like AFM and confocal microscopy, as well as viability assays to test the toxicity of the engineered liposomes to HeLa cells. Finally, we demonstrated the ability of the engineered liposomes to fuse with cells, acting as nanocarriers based on their physicochemical properties. The ability of the membrane model to mimic the HeLa cell lipid membrane was also validated. |
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