Synthesis, characterization and in vivo evaluation of biocompatible ferrogels

Abstract

A hydrogel is a 3-Dnetwork of polymer chains in which water is the dispersion medium. Hydrogels have found extensive applications inthe biomedical field due to their resemblance to living tissues.Furthermore, hydrogels can be endowedwith exceptionalproperties by addition of syntheticmaterials. For example, magneticfield-sensitive gels, called ferrogels, are obtained by embedding magnetic particles in the polymer network. Novelliving tissueswith unique magnetic field-sensitive propertieswere recently preparedby 3-D cell culture in biocompatible ferrogels. This talk critically reviews the most recent progress and perspectives intheirsynthesis, characterizationand biocompatibility evaluation. Optimizationof ferrogels for this novel applicationrequires low-density, strongly magnetic, multi-domain particles. Interestingly, the rheological properties of the resulting ferrogelsin the absence of field were largely enhanced with respect to nonmagnetic tissues, which can only be explained by the additional cross-linking imparted by the embeddedmagnetic particles.Remarkably, rheological measurements under an applied magnetic fielddemonstrated that magnetic tissuespresented reversibly tunable mechanical properties, which constitutes a unique advantage with respect to nonmagnetic tissues. In vivo evaluation of ferrogelsshowed good biocompatibility, with only some local inflammatoryresponse, and noparticle migrationor damage to distant organs.