Incorporation of curcumin extract with lemongrass essential oil into the middle layer of triple-layered films based on furcellaran/chitosan/gelatin hydrolysates - In vitro and in vivo studies on active and intelligent properties.

Triple-layered, pH-sensitive and active films based on furcellaran (FUR), chitosan (CHIT) and gelatin hydrolysates (HGEL) were obtained for the first time. Curcumin ethanol extract (CUR) enriched with lemongrass essential oil (LEO) in three concentrations was added to the middle layer of the film. SEM and AFM analysis confirmed the formation of 3 layers, and CUR-LEO was evenly dispersed in the 2nd layer. The addition of CUR-LEO influenced the color of the surface and improved the UV blocking properties of the film. However, the mechanical and water vapor barrier properties remained unchanged. The CUR-LEO demonstrated antibacterial properties against bacteria and fungi. The antioxidant activity of the films increased along with the increasing concentrations of CUR-LEO. The presented films were able to effectively extend the storage life of tomatoes. Moreover, the colored films had the monitoring freshness effect with a distinct color change during carp storage.

Structural evolution of supported lipid bilayers intercalated with quantum dots.

HYPOTHESIS: Supported lipid bilayers (SLBs) embedded with hydrophobic quantum dots (QDs) undergo temporal structural rearrangement. EXPERIMENTS: Synchrotron X-ray reflectivity (XRR) was applied to monitor the temporal structural changes over a period of 24 h of mixed SLBs of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) / 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-ethanolamine (POPE) intercalated with 4.9 nm hydrophobic cadmium sulphide quantum dots (CdS QDs). The QD-embedded SLBs (QD-SLBs) were formed via rupture of the mixed liposomes on a positively charged polyethylene imine (PEI) monolayer. Atomic force microscopy (AFM) imaging provided complementary characterization of the bilayer morphology. FINDINGS: Our results show time-dependent perturbations in the SLB structure due to the interaction upon QD incorporation. Compared to the SLB without QDs, at 3 h incubation time, there was a measurable decrease in the bilayer thickness and a concurrent increase in the scattering length density (SLD) of the QD-SLB. The QD-SLB then became progressively thicker with increasing incubation time, which - along with the fitted SLD profile - was attributed to the structural rearrangement due to the QDs being expelled from the inner leaflet to the outer leaflet of the bilayer. Our results give unprecedented mechanistic insights into the structural evolution of QD-SLBs on a polymer cushion, important to their potential biomedical and biosensing applications.