Design of Spherical Gel-Based Magnetic Composites: Synthesis and Characterization

The purpose of the study was the synthesis and the physicochemical characterization of spherical beads of magnetically active composite ferrogels (FGs) with diameters of 2-3 mm for further application to the needs of targeted drug delivery and/or replacement therapy. Spherical FGs based on a physical network of calcium alginate (CaAlg), a chemical network of polyacrylamide (PAAm), and a combined network of calcium alginate and polyacrylamide (PAAm/CaAlg) were analyzed. FGs were filled with ?-Fe2O3 magnetic nanoparticles (MNPs) obtained by using the electrical explosion of wire method. A comparative study of the swelling behavior and of the structural features of the polymeric network in CaAlg, PAAm/CaAlg, and PAAm spherical beads was performed. It was shown that the densest network was provided by a combination of chemical and physical networking in PAAm/CaAlg FGs. If the physical network were removed from FGs it resulted in a substantial increase in the average diameter and the swelling ratio of spherical beads and a decrease in the MNPs concentration in the swollen FGs by approximately two times. It was shown that irrespective of the gel composition, the embedding of maghemite nanoparticles led to an increase in the swelling ratio of the polymeric network. This indicated the absence of strong intermolecular interactions between the polymer and the filler. The results obtained might be useful for the design of magnetically active spherical FG beads of a given size and controlled physicochemical properties.

Automated summary

The study aimed to synthesize and characterize spherical beads of magnetically active composite ferrogels (FGs) for drug delivery and/or replacement therapy. The FGs were composed of calcium alginate (CaAlg), polyacrylamide (PAAm), and a combination of CaAlg and PAAm. The presence of chemical and physical networking in PAAm/CaAlg FGs provided the densest network. Embedding maghemite nanoparticles increased the swelling ratio of the polymeric network, indicating weak intermolecular interactions between the polymer and the filler. These findings are important for designing spherical FG beads with desired size and physicochemical properties.