One-pot synthesis of a chitosan-based hydrogel as a potential device for magnetic biomaterial

This describes the cross-linking/co-polymerization reaction of chitosan (CS), acrylic acid (AAc), and N, N′-methylenebisacrylamide (MBA) in the presence of citrate-covered-γ-Fe2O3 nanoparticules. A gelling process was verified by means of spectroscopic methods; Fourier transform infrared (FT-IR) and solid-state 13C-CP/MAS nuclear magnetic resonance (NMR). The corresponding signals of the gelling process, in the 13C NMR spectra, for the magnetic hydrogel were shifted to lower values due to embedding of the citrate-covered-γ-Fe2O3 nanoparticules. The X-ray diffraction (XRD) confirmed that the crystallinity of the magnetic hydrogel exhibited a different crystalline structure to that without magnetic properties. The Mössbauer and magnetization analysis revealed that the magnetic hydrogel displays a high lattice strain, due to bonded iron atom covalence and superparamagnetism. From scanning electronic microscope (SEM) micrographs, no separation phase coexists between the magnetic nanoparticules and cross-linked hydrogel, indicating an excellent dispersion throughout the hydrogel. The swelling rate was dependent on the cross-linking degree of the hydrogel and ionic strength of the aqueous solution.