Novel core-shell nanoparticles: Encapsulation and delivery of curcumin using guanidine hydrochloride-induced oleosome protein self-assembly

Guanidine hydrochloride (GuHCl) was used to disassemble and reassemble oleosome proteins (OP) to encap-sulate curcumin inside OP core-shell structures, improving its stability and bioavailability. The effect of GuHCl on the structure of OP indicated that OP disassembly and reassembly primarily involved the breakage and formation of hydrogen bonds. The extrinsic-protein subunits in OP were completely disassembled by GuHCl (5 M); after GuHCl removal by dialysis, the disassembled subunits were re-linked with intrinsic-protein subunits, encapsulating curcumin during the reassembly process. Curcumin preferentially bound with extrinsic protein of OP (through hydrogen bonding and hydrophobic interactions) to form protein-nanoparticle shells, while intrinsic-protein formed hydrophobic cores that encapsulated curcumin; the final curcumin encapsulation effi-ciency was 22.56 mu m/mg. Additionally, the curcumin-OP nanoparticles exhibited high stability and bioavail-ability (44.7%), and sustained-release behavior with GuHCl (5 M). This study elucidates and develops OP structures and could guide the development of high-efficiency nanoparticle delivery systems for hydrophobic nutrient carriers.