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Identifier 000455152
Title 1. Multifunctional scaffolds for bone tisse engineering : synthesis, characterization and in vitro evaluation 2.Visible light photopolymerizable hydrogels :Synthesis , characterization and in vitro evaluation
Alternative Title Πολυλειτουργικά τρισδιάστατα ικριώματα για εφαρμογές στη μηχανική ιστού 2Πολυμερισμός υδρογελών με ορατό φωςΧαρακτηρισμός and in vivo αξιολόγηση.
Author Παπαϊωάννου, Άννα
Thesis advisor Βαμβακάκη, Μαρία
Reviewer Χατζηνικολαϊδου, Μαρία
Μητράκη, Αννα
Abstract

1stHydrogels have been widely exploited for biomedical applications such as contact lenses, drug delivery. Their special properties of large pore size for permeation of nutrients, high swelling degrees and water absorption, cell encapsulation and also tunable mechanical properties make them the perfect candidates for tissue engineering applications as well. Photopolymerizable hydrogels synthesis can be an advantageous method in tissue engineering, introducing fast reaction rates, in situ gel formation at physiological temperatures and spatiotemporal control of polymerization. The main disadvantage of photopolymerization lies in the use of UV light for photoinitiation and photocrosslinking which can be toxic for the cells and can have adverse effects to their metabolic activity. This first part of this thesis, aims at the synthesis of photopolymerizable hydrogels by employing g-C3N4, widely known as a visible light photocatalyst as a visible light photoinitiator. Nanosheets of the photoinitiator that were synthesized employing two different green exfoliation methods were assessed for their biocompatibility and also three different photopolymerizable derivatives from dopamine, gelatin and alginate were synthesized to be explored in the hydrogel synthesis of copolymeric hydrogels. To establish the optimum reaction conditions, commercially available poly(ethylene glycol methyl ether methacrylate) with a molecular weight of 475 g/mol (PEGMA, Mw = 475 g/mol) was copolymerized with the in-house synthesized dopamine methacrylamide (DMA) comonomer via free-radical polymerization photo-initiated by g-C3N4 to obtain PEGMA-co-DMA hydrogels The catechol moieties of DMA enabled the self-crosslinking of the polymeric chains via hydrogen bonding, thus eliminating the need for an additional, and often toxic, cross-linker. The as-synthesized hydrogels exhibited swelling profiles which were dependent on their cross-link density, and remarkable degrees of swelling up to 2000%.

2nd.Hydrogels have been widely used in biomedical applications, such as drug delivery and tissue engineering. Their unique properties, providing a large network of pores for cell encapsulation and the permeation of nutrients, their high degrees of swelling and water absorption and the tunability of their mechanical properties, have established them as excellent candidates for use as tissue engineering scaffolds. Hydrogel synthesis via photo-polymerization/photo-cross-linking is an advantageous method enabling fast reaction rates, in-situ gel formation at physiological temperatures and a spatiotemporal control of the hydrogel formation process. The main disadvantage of the photo-polymerization/photo-cross-linking process lies in the use of UV light for photo-initiation/ photo-cross-linking, which can be toxic for the cells and have adverse effects to the cell’s metabolic activity, thus preventing its use in photo-polymerizable bioinks. To address this problem, the development of systems that can undergo photo-polymerization/photo-cross-linking under visible light is highly desired. In this thesis, we explore the synthesis of polymer hydrogels for use as tissue engineering scaffolds, using g-C3N4 as a novel visible light photo-initiator. Biodegradable hydrogels presenting a favorable environment for cell attachment and proliferation, were synthesized using gelatin methacrylamide (GelMA) and dopamine methacrylamide (DMA) as the comonomers. The GelMA-co-DMA hydrogels were prepared by photo-initiated polymerization/photo-cross-linking, using g-C3N4, in the absence of an additional cross-linker. The as-synthesized hydrogels exhibited swelling and degradation profiles which were dependent on their GelMA and DMA composition. Finally, composite hydrogels incorporating nanohydroxyapatite were synthesized and investigated as biodegradable 3D scaffolds for bone tissue engineering applications.

Language English, Greek
Subject Hydrogels
Issue date 2023-04-05
Collection   School/Department--School of Medicine--Department of Medicine--Post-graduate theses
  Type of Work--Post-graduate theses
Permanent Link https://elocus.lib.uoc.gr//dlib/8/9/9/metadata-dlib-1684482832-32208-30342.tkl Bookmark and Share
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Multifunctional scaffolds for bone tisse engineering :synthesis, characterization and in vitro evaluation

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Visible light photopolymerizable hydrogels :Synthesis , characterization and in vitro evaluation

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