A mechanistic approach to design smart scaffolds for tissue engineering

This thesis describes a library of novel 3D scaffolds designed and optimized for tissue engineering and regenerative medicine applications. Tissue engineering aims at restoring or regenerating a deamaged tissue by combining cells, derived from a patient biopsy, with a 3D porous matrix, functioning as a scaffold. After isolation\ud and eventual in vitro expansion, cells are seeded on the 3D scaffolds and, depending on the strategy, implanted directly or at a later stage in the patient¿s body

Biodegradable polymers based on trimethylene carbonate for tissue engineering applications

In the field of tissue engineering, the search for suitable materials for use in the preparation of scaffolds to host the developing tissue represents a major subject of study. Biodegradable materials show great potential in this area as, by resorbing upon performing their function, they obviate long-term biocompatibility concerns

The Use of Poly(vinyl alcohol)-based Hydrogels in Biomedical Applications

Polymers have found increasing favor in biomedical applications due to the greater control that researchers can exert over their properties. Researchers have focused on the development of therapies using biologically compatible polymers due to their ability to limit potentially harmful interactions with the body. This research has led to advances in tissue engineering, controlled and targeted drug delivery, and other biomedical fields, with the goal of improving both the effectiveness and accessibility of health care. Poly(vinyl alcohol) (PVA) hydrogels possess several chemical properties that make them well suited for biomedical applications. These include inertness and stability, biocompatibility, and pH-responsiveness. As a result, PVA based materials have been studied for potential applications in areas of biomedicine such as targeted drug delivery, tissue engineering, and wound healing. This thesis examines the properties of PVA and seeks to understand how the chemical and physical structure affects their properties. It then examines how these properties enhance their utility in potential biomedical applications. Finally, it reviews the research into development of PVA based materials for three different biomedical applications.Chemical Engineerin

Bacterial nanocellulose applications for tissue engineering

Nanocellulose is one of the most promising natural polymers to substitute conventional polymers currently employed for tissue engineering applications. The three different types of nanocellulose (cellulose nanocrystals, cellulose nanofibrils, and bacterial cellulose) are presented in this chapter. However, the main focus of discussion is bacterial cellulose (BC) for tissue engineering applications, owing to its meritorious properties such as physical (high purity, permeability, water absorption capacity, and porosity), mechanical (high tensile strength), and biological properties (good biocompatibility and biodegradability). These physical, biological, and mechanical properties of BC are features that enable BC membranes to function as effective temporary wound dressing biomaterial compared with conventional wound dressing materials. BC membranes can easily absorb exudate during wound dressing process and are smoothly removed from a wound surface after recovery. BC used for permanent implantation can remain in the body without causing any toxic or inflammatory reactions due to its good biocompatibility properties. In addition, BC membranes are developed in any shape and size, which enhance their suitability to cover large and difficult areas of the body. Hence, interest in BC biofabricated materials has accelerated steadily as a result of their remarkable potential usage in tissue engineering applications

Acrylic acid plasma coated 3D Scaffolds for Cartilage tissue engineering applications

Abstract The current generation of tissue engineered additive manufactured scaffolds for cartilage repair shows high potential for growing adult cartilage tissue. This study proposes two surface modification strategies based on non-thermal plasma technology for the modification of poly(ethylene oxide terephthalate/poly(butylene terephthalate) additive manufactured scaffolds to enhance their cell-material interactions. The first, plasma activation in a helium discharge, introduced non-specific polar functionalities. In the second approach, a carboxylic acid plasma polymer coating, using acrylic acid as precursor, was deposited throughout the scaffolds. Both surface modifications were characterized by significant changes in wettability, linked to the incorporation of new oxygen-containing functional groups. Their capacity for chondrogenesis was studied using ATDC5 chondroblasts as a model cell-line. The results demonstrate that the carboxylic acid-rich plasma coating had a positive effect on the generation of the glucoaminoglycans (GAG) matrix and stimulated the migration of cells throughout the scaffold. He plasma activation stimulated the formation of GAGs but did not stimulate the migration of chondroblasts throughout the scaffolds. Both plasma treatments spurred chondrogenesis by favoring GAG deposition. This leads to the overall conclusion that acrylic acid based plasma coatings exhibit potential as a surface modification technique for cartilage tissue engineering applications

Synthesis of hetero-bifunctional, end-capped oligo-EDOT derivatives

Conjugated oligomers of 3,4-ethylenedioxythiophene (EDOT) are attractive materials for tissue engineering applications, and as model systems for studying the properties of the widely used polymer PEDOT. We report here the facile synthesis of a series of keto-acid end-capped oligo-EDOT derivatives (n = 2-7) through a combination of a glyoxylation end capping strategy and iterative direct arylation chain extension. Importantly, these structures not only represent the longest oligo-EDOTs reported, but are also bench stable in contrast to previous reports on such oligomers. The constructs reported here can undergo subsequent derivatization for integration into higher order architectures, such as those required for tissue engineering applications. The synthesis of hetero-bifunctional constructs, as well as those containing mixed monomer units is also reported, allowing further complexity to be installed in a controlled manner. Finally, we describe the optical and electrochemical properties of these oligomers and demonstrate the importance of the keto-acid in determining their characteristics

Mechanical Properties of Natural Chitosan/Hydroxyapatite/Magnetite Nanocomposites for Tissue Engineering Applications

Chitosan (CS), hydroxyapatite (HA), and magnetite (Fe3O4) have been broadly employed for bone treatment applications. Having a hybrid biomaterial composed of the aforementioned constituents not only accumulates the useful characteristics of each component, but also provides outstanding composite properties. In the present research, mechanical properties of pure CS, CS/HA, CS/HA/magnetite, and CS/magnetite were evaluated by the measurements of bending strength, elastic modulus, compressive strength and hardness values. Moreover, the morphology of the bending fracture surfaces were characterized using a scanning electron microscope (SEM) and an image analyzer. Studies were also conducted to examine the biological response of the human Mesenchymal Stem Cells (hMSCs) on different composites. We conclude that, although all of these composites possess in-vitro biocompatibility, adding hydroxyapatite and magnetite to the chitosan matrix can noticeably enhance the mechanical properties of the pure chitosan