Informed manipulation of nanoliposome bilayer structure enhances the antioxidant activity and storage stability of curcumin.

This study investigated the impacts of Cur loading level on bilayer structures, antioxidant activities, and physicochemical stabilities of Cur-loaded nanoliposomes (NLs-Cur). Particle size, encapsulation efficiency, and lipid bilayer architecture were monitored in parallel with fluorescence spectroscopy, Raman spectroscopy, and differential scanning calorimetry (DSC). The results suggested that at low loading (0.05 wt%), Cur were embedded in the hydrophobic core of the bilayer, reinforcing vesicle integrity and resulting in improved stability. Increased Cur loading (0.10-0.20 wt%) promoted its localisation at the lipid-water interface loosening phospholipid packing and increasing bilayer fluidity that leads to a substantial enhancement in antioxidant activity. Excessive Cur loading (0.40 wt%) disrupted the acyl-chain packing, inducing bilayer disorder and membrane dilation, thereby compromising stability. Meanwhile, the NLs-Cur was decorated with (-)-epigallocatechin-3-gallate (EGCG) to specify the role and contribution of EGCG in liposomal systems. The results indicated that the EGCG partial embedded into the bilayer, which increased stacking density and decreased bilayer fluidity, which improved antioxidant performance and stability of NLs-Cur during storage. However, its contribution was relatively limited compared with Cur, revealing that EGCG acts as a supplementary stabilising component. Collectively, these findings offer valuable guidance for advancing liposomes delivery systems and broadening their application in personalized nutrition.