Characterization and preparation of hierarchical macroporous biodegradable polyhipe composites

The purpose of tissue engineering is to produce alternating viable synthetic tissue scaffolds to be used in the treatment of tissue loss caused by traumas and accidents. The most important features required for an ideal tissue scaffold are known to be biocompatibility and interconnected porous structure needed to the tissue growth by facilitating mass transport. In this respect, high internal phase emulsion (HIPE) templating is attracting considerable interest in the field of tissue engineering due to hierarchical pore morphology, high chemical resistance, permeability properties, and low density of the resulting materials. HIPEs are defined as concentrated emulsion systems consisting of a high ratio of internal (dispersed) phase. The volume fraction (Ø) of the internal phase of a HIPE is usually greater than 0.74 and can reach levels of 0.99. Polymerization of the continuous phase of HIPEs forms hierarchical porous polymers named "polyHIPEs". In this thesis study, macroporous biodegradable polyHIPEs with high mechanical strength and thermal stability have been prepared via emulsion templating. With this context, in order to obtain biodegradable polymer matrices, glycerol 1,3-diglyceroate diacrylate (GDA) have been used as the continuous phase in the preparation of HIPEs. The morphological properties of polyHIPEs obtained by the polymerisation of HIP emulsions have been investigated depending on the used emulsifier amount, internal phase ratio and continuous phase composition. Furthermore, in order to facilitate influence and migration of cells into the polymer matrix hydoxyapatite (HA) was added into the HIPE formulations and polyHIPE/HA composites have been prepared by the polymerization of these emulsions. Afterwards, the influence of HA amount on the morphological, mechanical and thermal properties of the resulting polyHIPE/HA composites have been investigated. In the last part, in vitro evaluation of the obtained polyHIPE/HA composites have been made in situmulated body fluid (SBF) and biodegradation behaviour have been investigated depending on time. Keywords: emulsion templating, polyHIPE composite, hydroxyapatite, biodegradation