Chitosan and carboxymethyl cellulose-multilayered magnetic fluorescent systems for reversible protein immobilization

Magnetic fluorescent nanoparticles (MFNPs)-based protein immobilization systems were successfully synthesized via a layer-by-layer (LbL) assembly approach in an impinging stream-rotating packed bed, which adopted chitosan containing carbon dots (CDs)@Fe₃O₄ nanoparticles (NPs) as a precursor, chitosan (CS) or carboxymethylcellulose (CMC) involving CDs as shells. To reveal the relationship between structure and efficiency of systems, the effect of self-assembly mode and layer number\was investigated to provide us insight into how to improve the design of MFNPs-based supports. Finally, an MFNPs-based protein immobilization system with excellent fluorescence and magnetic response, expanded specific surface area, and enhanced immobilization and release performance were obtained. Immobilization mechanism and kinetic studies were also conducted to reveal the rate-controlling step and the template affinity. Taken together, this study provides an effective strategy to synthesize bifunctional MFNPs and to adjust the performance, which aims for facilitating new possibilities for biomass-based nanomaterials used for protein immobilization.