Περίληψη |
Aliphatic polyesters have been extensively used in the biomedical field, for tissue engineering
applications. Despite their numerous benefits, such as biocompatibility and biodegradability, these
materials are mostly inert and lack specific functionalities that would provide them with extra
biological and responsive characteristics, such as pH, temperature, mechanical stimuli etc.,
whereas the synthetic route followed usually requires multistep synthesis with strict conditions.
In this work, pH-responsive aliphatic polyesters have been prepared by a facile condensation
polymerization of a vinyl functionalized diol with a diacid chloride, followed by a carboxylic acidfunctionalization along the polymer chains, via a photo-induced thiol-ene click reaction. The postsynthesis functionalization was conducted using two different mercaptocarboxylic acids, namely
3-mercaptopropionic and thioglycolic acid allowing the variation of the alkyl chain length of the
side pendant groups. Furthermore, by adjusting the irradiation period during the click reaction,
the degree of modification, and hence the carboxylic acid content of the polymers, could be easily
controlled. Both of these characteristics were shown to have a significant impact on the responsive
behavior of the polyesters with adjustable pKa values and water solubilities. To assess the
biological properties of the materials in vitro, thin film of the difunctional polyesters bearing both
alkene and carboxylic acid moieties were prepared by chemically linking the pendant vinyl bonds
of a silanized substrate with the polymers’ side groups. The polymeric thin films with the shorter
alkyl chain and the highest functionalization degree (PE-Glyc50) were found to promote greatly
the cell viability, proliferation, and attachment when assessed in L929 fibroblast cultures. Next the
PE-Glyc50 polyester, as well as a blend of the same polyester with laponite, were blended with
PEGDMA as the crosslinker, to develop stable 3D scaffolds via an extrusion-based printing
method. Finally, the optimized printing conditions resulted in structures that were investigated for
their degradability and the influence of the pH on their swelling behavior, porosity.
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