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Identifier 000443195
Title 4D printing of biomaterials scaffolds for Tissue Engineering
Alternative Title Τετραδιάστατη εκτύπωση ικρυωμάτων απο βιουλικά για μηχανική ιστών
Author Χανιωτάκη, Λευκή
Thesis advisor Στρατάκης, Εμμανουήλ
Reviewer Μητράκη, Άννα
Κιοσέογλου, Γεώργιος
Abstract The use of Fused Filament Fabrication 3D printer has been launched in the last decade as it is easy to use and accessible to everyone. It is a common way to alter the surface of the 3D printed scaffold after is printed with subtractive manufacturing techniques. The most well-known subtractive techniques used are either with laser (ablation, cutting and others) or with chemical etching. Although, with laser induced ablation or micromachining, you could abstract more specific, small designs up to the diffraction limit and use a variety of materials. Until now, they only alter the surface of the scaffolds and at some of them the second layer by changing of the focus. In this way, you could alter the surface of the scaffold with designs more complex and smaller than the resolution of the FFF 3D printer or you could make it more porous. In this research project, we combined the subtractive and the additive manufacturing technique to construct advanced 4D scaffolds with PLA for tissue engineering applications. In this work, we changed 2 set-ups before we ended up with the last and better set-up where we combined the Ytterbium Picosecond Fiber Laser, wavelength 1060 nm, a galvo scanner and Fused Filament Fabrication (FFF) 3D printer. The use of Galvo was to scan surfaces 100 times faster and to have less vibrations. Moreover, there are many techniques to make 3D scaffolds, but the FFF is a cheap technique, with resolution approximately 100 μm. With combination of laser and galvo, we managed to make designs that can cover resolution from 1μm to macro scale. So, we could construct ablated structures at any layer of the 3D scaffold and more complex internal designs with laser, with smaller resolution than that of the 3D printer. Also, this combination is material impendent. In addition, there are some biocompatible polymeric filaments (PLA, PCL, PLGA, PEEK, PET, PLLA) but the most well-known and FDA approved is the natural PLA which is the one that we used. PLA is capable for tissue engineering applications because it is biocompatible, biodegradable and it is used in a wide range of applications such as biomedical. To achieve this novel and advanced 4D printing mix-and-match, we performed many changes at the ender 3 pro printer, we constructed an optical path, and we worked on a new more functional program with python. We could ablate circles, lines and spots only with galvo or we could 3D print designs or we could ablate designs with laser, or we could combine them. Furthermore, we could do many changes in the laser’s design such as minimize its dimensions at xy axis, multiply the laser’s design, choose the layers that the laser ablation started and stopped and others. Finally, we managed to make a successful combination of additive manufacturing and subtractive technique to make 4D scaffolds with PLA for tissue engineering applications. We characterized them with SEM (structural and morphological properties), UV-Vis (optical properties after laser treatment) and contact angle measurements. At last, the interaction of these 4D scaffolds with MSC cells was 6 investigated. Specifically, we studied MSCs proliferation and morphology with SEM. We also observed the effect of the 4D scaffolds in terms of cell cytoskeleton (actin Phalloidin), cell mechanotransduction (YAP/TAZ), cell nucleus (DAPI) and finally osteopontin (OPN) to observe if they will actually differentiate to osteogenic lineage with and without osteogenic differentiation medium at different time points via confocal microscopy
Language English
Subject Τρισδιάστατος εκτυπωτής
Issue date 2021-11-26
Collection   School/Department--School of Sciences and Engineering--Department of Materials Science and Technology--Post-graduate theses
  Type of Work--Post-graduate theses
Permanent Link https://elocus.lib.uoc.gr//dlib/2/7/f/metadata-dlib-1635330460-586201-4921.tkl Bookmark and Share
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