Viscoelastic hydrogels from poly(vinyl alcohol)–Fe(iii) complex

Abstract

Hydrogels are three dimensional scaffolds of hydrophilic polymers with inter-connected water channels. In this investigation, an interesting approach for the fabrication of a highly viscoelastic hydrogel derived from a polyvinyl alcohol (PVA) based macromer is reported. PVA was crosslinked using Fe³⁺ ions under basic conditions to obtain a stable hydrogel with a highly porous network structure. The swelling ratio of the designed hydrogels was evaluated and correlated to the network structure of the metal coordinated crosslinked macromers. Compressive modulus and dynamic viscoelastic measurements were carried out using a dynamic mechanical analyzer and no significant changes in storage modulus were observed by increasing the temperature up to 45 °C. A creep study revealed that the elastic recovery was enhanced with an increase in the degree of crosslinking. The effect of crosslinking influenced properties such as the glass transition, melting point and melting enthalpy of the crosslinked network. The cytocompatibility of the gels was studied using human lung fibroblasts (IMR-90) and no toxic effects or significant cell attachments were observed on the surface of the gel after 5 days. The designed hydrogels may be useful for biomedical procedures which require highly viscoelastic, biocompatible, thermally and mechanically stable biomaterials.