NANOSTRUCTURED AND NANOCOMPOSITE HYDROGELS FOR BIOMEDICAL APPLICATIONS

摘要

Polymer hydrogels are interesting for biomedical applications due to their biocompatibility and good water sorption/diffusion properties. In previous work their mechanical stability could be improved by combination with a hydrophobic polymer. Instead, here we prepare poly(hydroxyethyl acrylate), PHEA/silica nanocomposites by sol-gel techniques as potential scaffold materials for tissue engineering. Their morphology and properties were investigated by scanning electron microscopy, thermogravimetry, dynamic mechanical analysis, water sorption/desorption, dielectric spectroscopy, and thermally stimulated depolarization currents techniques at various levels of relative humidity/water content. The results show that the nanoparticles are homogeneously distributed, form a continuous phase, and significantly reinforce the matrix, without affecting its hydrophilicity and, thus, biocompatibility. Water is more homogeneously distributed, as compared to pure PHEA matrix, forming smaller clusters. The glass transition temperature is controlled by water content, and less affected by the concentration of silica.