Novel green synthesized agar/alginate biopolymer hydrogel-based magnetic composite beads for biomedical,...

Novel, eco-friendly, and biocompatible bi-biopolymer magnetic composite beads were synthesized by integrating sodium alginate and agar with iron oxide (Fe₃O₄) and green tea-mediated manganese oxide (MnO) nanoparticles. The bi-biopolymer magnetic composite beads prepared with varying contents (10.15-30%) of MnO nanoparticles were systematically characterized using FTIR Spectroscopy, SEM, EDX, XRD, TGA, BET analysis, and electrical conductivity analyses, confirming uniform nanoparticle dispersion and strong polymer matrix-nanoparticle interactions. Among the synthesized formulations, 30%@SAMN (sodium alginate-agar magnetic nanocomposite beads) exhibited superior adsorption performance, achieving approximately 99% methylene blue removal at pH 9 using a 0.01 g adsorbent dose with equilibrium reached within 10 min. The enhanced adsorption efficiency was attributed to increased surface roughness, higher porosity, and abundant active adsorption sites resulting from higher MnO nanoparticle incorporation and synergistic interaction with Fe₃O₄ nanoparticles. Adsorption kinetics followed the pseudo-second-order model, while equilibrium data showed excellent agreement with the Langmuir isotherm with a maximum adsorption capacity of 61.25 mg g^-1. Thermal and swelling analyses revealed enhanced crosslinking and thermal resistance with increasing MnO incorporation. The nanocomposite beads also demonstrated remarkable multifunctionality, showing strong antibacterial, antioxidant, anti-inflammatory, and antidiabetic properties along with promising hemostatic and electrical performance. Overall, the results highlight the successful development of a high-performance, thermally stable, and magnetically responsive nanocomposite with broad potential applications in environmental remediation, biomedical engineering, and advanced material systems.