Post-graduate theses
Search command : Author="Στεφανίδης"
And Author="Κωνσταντίνος"
Current Record: 4674 of 6548
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| Identifier |
000036737 |
| Title |
Ανάπτυξη Βιολογικών Μικροσυστοιχιών με τη Μέθοδο Απευθείας Μεταφοράς με Laser και Μελέτη του Μηχανισμού Μεταφοράς |
| Alternative Title |
Microfabrication of Biopolymer patterns by means of Laser Induced Forward Transfer Technique and analysis of the printing process |
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Author
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Καραΐσκου, Άννα
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Thesis advisor
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Φωτάκης, Κωνσταντίνος
Ζεργιώτη, Ιωάννα
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| Abstract |
The main goal of this study is the development of biological microarrays by means of the Laser Induced Forward Transfer technique (LIFT). Precise deposition of biopolymers such as proteins, nucleic acids and oligonucleotides, has been the basis for the development of various research, analytical and diagnostic applications such as biosensors, dipstick tests, protein and nucleic acid microarray chips and microfluidic assay technologies. The LIFT technique utilizes pulsed lasers to selectively remove biological thin film material by means of an ablation process. The target biopolymer is provided in the form of a coating upon the front surface of a laser transparent support. The pulsed laser beam shape and dimensions when projected onto the target material can be adjusted by means of a variable aperture. The receiving substrate should be placed in parallel and in close proximity with the target substrate. Both receiving and target substrates are placed in a holder fixed onto a computer controlled x-y translation stage, allowing a maximum movement of 25 mm΄ 25 mm, by means of piezoelectric motors, having a 50 nm positioning resolution determined by optical encoders. Repeating the transfer process at different target and substrate positions, results in the production of extended patterns such as arrays of features, or localized coatings. As far as the efficiency of the biomaterial transfer method is concerned, different experimental parameters should be taken into account. The precise fabrication of micro-dimensioned patterns of biomaterials, such as lambda bacteriophage DNA and proteins into various substrates are reported in this thesis. The laser source was a Lambda Physic distributed feedback dye laser emitting 500 fs duration pulses at 248 nm. The ablation process of the biomaterials is accomplished into a miniature vacuum cell in order to avoid splattering due to collisions of the transferred structures with surrounding air. The morphology of the printed features has been studied by means of Scanning Electron Microscopy and optical microscopy. The main advantage of this transfer process is the high resolution of the spots and the extremely high density of the arrays (108 / cm). A laser confocal scanner has been used in order to ensure the functionality of the DNA in hybridization reactions and of the proteins in protein-protein interactions. The quality of the deposited material has been also asserted by means of gel electrophoresis and by Southern hybridization experiments. Our results demonstrate that a laser based processing technique can be used to directly write micro-patterns of sensitive biological materials without destroying their functionality, while the fabricated microarrays are suitable for downstream hybridization analysis and studies of protein-proteins interactions. The time resolved Schlieren imaging process, streak camera and ICCD experiments have been applied to investigate the process mechanism, for various delay times following the laser irradiation pulse. The results of the above measurements have shown that the biomaterial is not ionized during the ablation process, while the whole material is removed according to the propagation of rarefaction waves. The material velocity has been measured up to 530 m/sec, and the high directionality of the ejected material for ultrafast laser printing pulses, leads to higher spatial printing resolution and superior deposition quality of the biomaterials.
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| Language |
Greek |
| Issue date |
2003-03-24 |
| Collection
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School/Department--School of Sciences and Engineering--Department of Chemistry--Post-graduate theses
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Type of Work--Post-graduate theses
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| Permanent Link |
https://elocus.lib.uoc.gr//dlib/d/d/e/metadata-dlib-2003karaiskou.tkl
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| Views |
204 |
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