Hypothesis: The biodegradable and biocompatible hydrogels from bio-based polymers are widely used in various biomedical applications, including drug delivery, tissue engineering, and wound healing. This study hypothesizes that by grafting acrylamide onto kappa-carrageenan and incorporating magnetic Fe₃O₄ nanoparticles, a hydrogel with improved properties is developed with potential for broad biomedical applications
Methods: A nanocomposite hydrogel, K-carrageenan-grafted-polyacrylamide/Fe₃O₄ (kC-g-PAAm/Fe₃O₄), was synthesized. The process involved the preparation of Fe₃O₄ nanoparticles and the modification of kC polysaccharide through acrylamide graft polymerization. Cross-linking reactions between polymer chains and the incorporation of Fe₃O₄ nanoparticles in the hydrogel matrix were carried out during the polymerization process. The chemical, morphological, thermal stability, magnetic behavior, and porosity properties of the nanocomposite hydrogel were characterized 
Findings: TXRD analysis revealed that the nanocomposite hydrogel exhibited characteristic peaks corresponding to Fe₃O₄ and kC, indicating an improvement in crystallinity compared to pure kC-g-PAAm. TGA results showed that the nanocomposite had significantly higher thermal stability compared to pure k-carrageenan, with a residual weight of 21% at 800 °C. VSM analysis demonstrated superparamagnetic properties, with a saturation magnetization of 12.173 emu g-¹ Furthermore, BET surface area analysis indicated that kC-g-PAAm had a specific surface area of 200.55 m².g-¹, significantly higher than that of pure kC, which was attributed to the three-dimensional network formed through graft polymerization and cross-linking reactions. Swelling experiments revealed that the kC-g-PAAm hydrogel absorbed as much as 2200% of water, while the kC-g-PAAm/Fe₃O₄ sample showed a slightly lower swelling capacity of 2080%, due to the nanoparticles restricting the network's flexibility. Gel content analysis indicated that the retained gel fractions were 74% and 81% for kC-g-PAAm and kC-g-PAAm/Fe₃O₄, respectively, demonstrating enhanced network stability in the presence of nanoparticles. These findings suggest that the synthesized nanocomposite hydrogel exhibits improved properties for biomedical application.