Model protein BSA adsorption onto novel magnetic chitosan/PVA/laponite RD hydrogel nanocomposite beads

Chitosan-based magnetic beads were developed by solution-mixing method. Firstly, the Fe3O4 nanoparticles were in situ immobilized on laponite RD sheets. The magnetic laponite RD was then dispersed in PVA and mixed with chitosan solution. PVA was aimed to prevent the disintegration of chitosan under acidic media due to its ability to form hydrogel network through freezing-thawing method. The manufactured magnetic chitosan/PVA/laponite RD beads were utilized for adsorption study of a model protein, bovine serum albumin (BSA). The adsorption of BSA on beads was pH-dependent where smaller mass of protein was adsorbed at pH values lower than isoelectric point of BSA. Moreover, it was discovered that introduction of magnetic laponite RD can improve the adsorption capacity of magnetic beads for BSA in which hydrogel with the highest content of magnetic laponite RD demonstrated the maximum adsorption capacity for BSA (qm = 240.5 mg/g). Langmuir model described the isotherm data better than Freundlich model.