Magnetoactive Properties of Biocompatible Magnetic Hydrogel Composites: Effects of Magnetic Particulate Type, Loading content and Magnetic Poling

Polyvinyl alcohol (PVA) ferrogels were successfully fabricated by the freezing-thawing (FT) cycle technique, employing magnetite (Fe3O4) and strontium ferrite (SrFe12O19) as the materials for magnetic, micron-sized, additives. Ferrogels are magnetic hydrogel composites commonly utilized in tissue engineering, and drug delivery. The hydrogels’ similarity to biological tissue and use of smart additives leads them to be uniquely well suited for biomedical applications. The differing effects of magnetically soft and hard additives on the properties of PVA ferrogels were investigated by comparing the magnetic, magnetoactive, and mechanical properties of magnetically soft and hard PVA ferrogels, respectively. The effects of magnetic polling on ferrogels were investigated in this study and were compared to analogous, non-poled samples. Magnetic properties were determined via analysis of sample hysteresis loops, generated via vibrating sample magnetometer (VSM).  Magnetoactive properties are determined by quantifying the angle of sample deflection in an applied transverse magnetic field, via a custom digital image overlay program. Mechanical properties are determined via tensile testing. Magnetic additive distribution was investigated using scanning electron microscopy (SEM). Results yielded magnetically hard ferrogels that allow for more complex actuation and highly magnetoactive magnetically soft ferrogels with tunable responsiveness based upon magnetic particulate type, content, and effects of magnetic poling.