Formation of ferritin-agaro oligosaccharide-epigallocatechin gallate nanoparticle induced by CHAPS and partitioned by the ferritin shell with enhanced delivery efficiency

Ferritin naturally has a shell-like architecture with inner/outer surfaces, which can be applied as a nanovehicle of biologically active molecules. Herein, a CHAPS-involved scheme was arranged to fabricate the ferritin-agaro oligosaccharide-epigallocatechin gallate (EGCG) nanoparticle (FAE) partitioned by the ferritin shell. A concentration (10 mM) of CHAPS expanded the channel size of phytoferritin by remarkably improving the rate of iron release and facilitated the encapsulation of EGCG without disassembling the ferritin. The encapsulating ratio of EGCG reached (10.8 ± 0.13) %, about 17.2 EGCG per ferritin cage. Meanwhile, agaro oligosaccharide could attach on the ferritin outer surface with a stoichiometric number of 12.1 ± 0.31 (agaro oligosaccharide/ferritin) and a binding constant of (3.25 ± 0.23) × 105 M−1. The diameter of FAE was maintained at ∼12 nm, and the hydrodynamic radius (RH) was 7.61 nm, proving that the agaro oligosaccharide attachment and the encapsulation of EGCG retained the ferritin morphology. In addition, the CHAPS acted in alleviating the association effect of the ferritin when forming FAE. Moreover, the agaro oligosaccharide as the second layer attaching on the ferritin surface significantly improved the EGCG stability in FAE towards heating treatment and controlled the release of EGCG in a more sustained manner. This study highlights the role of CHAPS and fabricates a triple-layer nanoparticle in a simple way, which expands the fabrication method of oligosaccharide-protein-polyphenol polymers and is conducive to the stability of food bioactive molecules.