Layer-by-layer self-assembly of hollow dextran sulfate/chitosan-coated zein nanoparticles loaded with crocin: Fabrication, structural characterization and potential biological fate

Crocin is a water-soluble carotenoid and has shown potential to improve the neurodegenerative disease such as Alzheimer's disease (AD). However, its application is limited due to the high instability and susceptibility to process conditions. Here, hollow dextran sulfate/chitosan (DS/CH)-coated zein nanoparticles (NPs) loaded with crocin using sodium carbonate as a sacrificing template were fabricated by a layer-by-layer (LbL) self-assembly technique. The mean particle size, polydispersity index (PDI), encapsulation efficiency, zeta potential, morphology (e.g. TEM and AFM), and FTIR observation revealed that the surface of crocin-loaded LbL hollow zein NPs was generated by the deposition of polyelectrolyte through electrostatic interactions, hydrogen bonding, and hydrophobic interactions. In vitro simulated gastrointestinal digestion and antioxidant activity assays indicated that the NPs exhibited better controlled release behavior and stronger antioxidant activity than that of uncoated crocin-loaded zein NPs dispersed in water. Moreover, the study of the potential effect of the NPs on AD cell model showed that the amyloid-β (Aβ1-42) concentration of differentiated SH-SY5Y cells decreased from 300 pg/mg to 170 pg/mg. These results reveal that LbL self-assembly of hollow DS/CH-coated zein NPs loaded with crocin can be developed as a promising delivery system for effective therapeutic approach of AD, and provide a new practical technique for delivering bioactive ingredients.