Fabrication of functional magnetic cellulose nanocomposite membranes for controlled adsorption of protein

Cellulose nanocomposite membranes with predesigned functions were prepared and evaluated as adsorbents for protein adsorption. Maghemite nanoparticles (MNP) with amino groups and carboxyl groups were obtained by modifying maghemite nanoparticles with glycine and sodium citrate, respectively. The functional maghemite nanoparticles were then dispersed into NaOH/urea aqueous solution for dissolving cellulose, and the magnetic membranes were constructed using a tape casting method. The modified MNP were evaluated by zeta potential and FTIR measurements. The developed cellulose nanocomposite membranes possess microporous structure with porosity higher than 88.3%. The introduction of MNP with carboxyl groups into the cellulose nanocomposite membranes could absorb the highest amount of protein at a pH of 4, and gradually decreased with the increase of pH from 4 to 6. However, cellulose nanocomposite membranes with introduced MNP with amino groups absorb the highest and lowest amount of protein at pH of 5 and 4, respectively. This study provides a green and simple method for the design of multifunctional cellulose nanocomposite membranes for controllable protein adsorption, and is expected to open new venues for biomolecule binding by choice of various nanofillers and pH of the medium.