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| Identifier |
000383132 |
| Title |
Determination of lipid depositions via the realization of nonlinear imaging measurements and correlation of the data with specific biological processes of various samples |
| Alternative Title |
Προσδιορισμός λιπιδικών εναποθέσεων και συσχέτισή τους με τη λειτουργία βιολογικών δειγμάτων μέσω καταγραφής μή γραμμικών απεικονιστικών μετρήσεων |
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Author
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Γαυγιωτάκη, Ευαγγελία
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Thesis advisor
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Φωτάκης, Κωνσταντίνος
Φιλιππίδης, Γεώργιος
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Reviewer
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Αθανασάκη, Ειρήνη
Λουκάκος, Παναγιώτης
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| Abstract |
Nonlinear optical processes have found widespread application in fields ranging from fundamental physics to biomedicine. Specifically, Third Harmonic Generation (THG) seems to be a suitable imaging tool for the delineation and quantification of biological structures at the microscopic level. In an isotropic medium, THG using focused femtosecond (fs) beams as excitation sources is possible only when an inhomogeneity is present in the focal volume. This property by itself already makes THG an ideal tool, since microscopic contrast is realized from the inherent properties of the sample and does not require additional labeling. In addition, the nonlinear nature of the interaction provides THG with inherent three dimensional imaging capabilities when using focused fs laser beams.
In this thesis, we attempted to understand the activation of cancer cells by using the THG imaging microscopy as a diagnostic tool and the BV-2 microglia cell line as a representative biological model.
Firstly, Third Harmonic Generation (THG) and Two Photon Excitation Fluorescence (TPEF) measurements were simultaneously collected from stained BV-2 cells, by employing a single homemade experimental apparatus, for the exact identification of the subcellular biological structures that gives high THG signals. Three different dyes in both cases of activation (control- activated cells) were used. It was shown that high THG signals arise mostly from lipid depositions.
Furthermore, in this study we used the THG microscopy to quantify the changes of mean total area and mean THG intensity values of lipid droplets before and after activation. THG imaging measurements provide a quantitative description of internal structures (lipid droplets), without staining. Activated BV-2 cells present higher lipid concentration and THG intensity values in comparison with the control cells.
Finally, we quantified the BV-2 cell line in different feed conditions Differences of mean total area and THG values of intensity of lipid droplets were investigated. Discrimination between control and activated BV-2 cells in three different feeding conditions was achieved.
The obtained results are very encouraging for the potential employment of THG imaging modality as a non-destructive diagnostic tool for cancer research.
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| Language |
English |
| Subject |
Biophotonics |
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Imaging by third harmonic generation |
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Nonlinear Microscopy |
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Απεικόνιση με γένεση τρίτης αρμονικής |
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Βιοφωτονική |
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Μη γραμμική μικροσκοπία |
| Issue date |
2014-03-28 |
| Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Post-graduate theses
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Type of Work--Post-graduate theses
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| Views |
625 |
Determination of lipid depositions via the realization of nonlinear imaging measurements and correlation of the data with specific biological processes of various samples
