Anisotropic mechanical behavior of rod-macroporous biocompatible hydrogels: physicochemical and mechanical characterization.Tuesday (27.09.2016) 15:30 - 15:45 Part of:
Crosslinked hydrogels based on N-isopropylacrylamide(NIPAM) and copolymerized with 2-acrylamido-2-methylpropanesulfonic acid(AMPS) or N-acryloyl-tris-(hydroxymethyl) amino methane(HMA) are studied. These are synthesized by free radical polymerization at room temperature and by cryogelation at -18ºC. The hydrophilic comonomers no only increases the phase transition temperature of hydrogels but also together with the reaction conditions affect the physicochemical, morphology and mechanical properties of the materials. The scanning electron microscopy(SEM) reveals that longitudinal and interconnected or spherical and isolated macropores are obtained by cryogelation. Tree different water states (strongly bound, weakly bound and free) are observed by differential scanning calorimetry(DSC) in the swollen macropores. Most of hydrogels show elastic modules (E) around 2-7 kPa obtained by uniaxial compression. However, higher E values (20-30 kPa) and an anisotropic mechanical behavior are observed for hydrogels with rod-like pores. When pressure is applied on parallel direction to longest axis of pore E is significantly higher than when pressure is applied on perpendicular direction, mimicking so the behavior of bones. Cytocompatibility studies using bovine fetal fibroblasts(BFF) indicate good cell attachment and proliferation on these hydrogel surfaces. The characteristic of these materials allow proposing its use in the fabrication of surface or scaffolds for possible study like graft or replacement of biological tissue.