LAUSR

Self-assembled and cross-linked hybrid hydrogels for entrapment and delivery of hydrophilic and hydrophobic bioactive compounds were developed based on N-acetyl-L-cysteine (NAC) or L-cysteine (CYS) functionalized chitosan-β-lactoglobulin nanoparticles (NPs). In both systems, amphiphilic protein β-lactoglobulin (β-lg) were self-assembled by glutaraldehyde for the affinity binding with egg white-derived peptides (EWDP) and curcumin, and then coated with NAC or CYS functionalized chitosan (CS) by electrostatic interaction. The resulting NPs were characterized in terms of size, polydispersity, and surface charge by dynamic light scattering. Results corroborated pH-sensitive properties of NAC-CS-β-lg NPs and CYS-CS-β-lg NPs with particle size as small as 118 and 48 nm, respectively. The two kind of NPs also showed excellent entrapment of EWDP and curcumin with the entrapment efficiency (EC) of EWDP and curcumin ranging from 51 to 89% and 42 to 57% in NAC-CS-β-lg NPs, as well as 50 to 81% and 41 to 57% in CYS-CS-β-lg NPs under different pH values. FT-IR and molecular docking studies provided support for the interaction mechanism of NAC/CYS-CS with β-lg as well as the NPs with EWDP and curcumin. Strikingly, the in vitro release kinetics of EWDP and curcumin exhibited the controlled and sustained release properties up to 58 and 130 h from the NPs, respectively. Of note, the permeability of QIGLF (pentapeptide, isolated from EWDP) and curcumin passing through Caco-2 cell monolayers were all improved after the entrapment in the NPs. This work offers promising methods for effective entrapment and oral delivery of both hydrophilic and hydrophobic bioactive compounds.