pH-sensitive self-assembled nanofibers based on electrostatic interaction and Schiff base bonding for controlled release of curcumin

In this study, chitosan-dialdehyde-β-cyclodextrin-curcumin (CS-DCD-CUR) and alginate dialdehyde (ADA) were alternately deposited on the surface of electrospun cellulose acetate (CA) nanofibers driven by Schiff base bonding and electrostatic attraction. With the increasing number of bilayers, the self-assembled nanofibers showed an increased average fiber diameter from 441 to 576 nm and had relatively rough surfaces. The improved thermal stability and tensile strength of self-assembled nanofibers were attributed to the interactions between CS-DCD-CUR and ADA. The self-assembled nanofibers exhibited pH-sensitive release characteristics under acidic conditions due to the weakening of the electrostatic interaction and the hydrolysis of Schiff-base. Moreover, the self-assembled nanofibers could be used for sustained and controlled release of the curcumin within 620 min and maintained the antioxidant activities. The highest radical scavenging activities against ABTS and DPPH radicals of the nanofibers were 24.75% and 83.56%, respectively. These results suggested that the layer-by-layer self-assembled nanofibers provided a pH-responsive sustained delivery system for bioactive substances with potential applications in functional foods.