Design of hybrid fibers for bone tissue engineering
Most of the conventional organic-inorganic composite materials developed for bone tissue engineering do not possess intimate interactions between their constituents. As a consequence, they generally degrade in a non-homogeneous manner and lose easily their integrity under mechanical load. On the oth...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/95602 |
| Acceso en línea: | https://hdl.handle.net/2117/95602 https://dx.doi.org/10.5821/dissertation-2117-95602 |
| Access Level: | acceso abierto |
| Palabra clave: | Enginyeria de teixits Materials compostos Materials biomèdics Àrees temàtiques de la UPC::Enginyeria dels materials |
| Sumario: | Most of the conventional organic-inorganic composite materials developed for bone tissue engineering do not possess intimate interactions between their constituents. As a consequence, they generally degrade in a non-homogeneous manner and lose easily their integrity under mechanical load. On the other hand, their bioactive phase (i.e. inorganic) is often masked by the polymeric one, resulting in a non optimal bioactivity. To overcome these problems, hybrid materials can be produced. Hybrids are composites that exhibit an improved synergy between their compounds at the nanoscale. Using the sol-gel method and the electrospinning technique, it has been possible to deposit two kinds of hybrid fibers: one constituted by a Si-Ca-P2 bioactive ormoglass (organically modified glass) and polycaprolactone, and the other by a Ti-Ca-P2-Na2 bioactive ormoglass and polylactic acid. In addition to the sol-gel method, the use of ormoglasses aimed to improve the interactions between the constituents by combining phases of similar nature (organic fragments introduced in the glass network). Both biomaterials showed a promising potential for bone regeneration due to their inherent composition and ability to trigger specific cellular responses such as osteo and angiogenesis. Based on previous studies performed by our group, it was hypothesized that, combined with the other chemical and physical intrinsic properties of the materials, the calcium ions released from the materials played an important role in the promotion of these biological performances. Though, the interactions between the phases in such hybrids are considered as "weak" because they are simply prepared by blending the different compounds together. In fact, a study performed on the degradation of polylactic acid/Ti-Ca-P2-Na2 ormoglass fibers revealed that the materials resorbed in a heterogeneous and rapid manner. Therefore, a new protocol has been implemented to create hybrid fibers with strong chemical interactions between the ormoglass and the polymer. This strategy is based on a coating approach (polylactic acid fibers coated with an ormoglass) and enables the fabrication of scaffolds with controllable properties (surface roughness, composition, stiffness). This can be achieved by modifying the ormoglass composition itself or the level of hydrolysis of the ormoglass precursor solution, for example. One advantage of this approach is moreover the possibility to apply this coating strategy to other structures and, potentially, to other ormoglass systems. This protocol represents thus a significant step forward towards the development of functional artificial 3D biomaterials aimed for tissue engineering. From a general point of view, the work reported in this thesis demonstrates that polymer-ormoglass hybrid materials can be shaped as biomimicking fibrous structures, they are promising for the tissue engineering field and their properties can easily be tailored. Knowing that cells modulate their behavior according to the physical and chemical signals that they receive from artificial matrices, the development of these materials opens valuable perspectives of work for the future, especially in terms of materials' design. |
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