Analysis of Fabricated Liposome

Particle size and particle size distribution (Polydispersity index, PDI) of liposomes were analyzed by a dynamic light scattering (DLS) apparatus (Zetasizer 3000 HSA, Malvern, U.K.) at 25 ◦C, and the light scattering angle was 90◦. To determine the amount of EGCG encapsulated in liposomes, EGCG-loaded liposomes were placed in a sealed dialysis membrane (MWCO = 1000). The membrane was placed in an isotonic aqueous solution at 4 ◦C for removing the EGCG molecule that was not encapsulated. Then, dialyzed liposomes and ethanol were reacted at 4 ◦C for 20 min for rupturing liposomes, and the solution was centrifuged at 10,000 rpm for 20 min at 4 ◦C in a high-speed centrifuge. The supernatant of the centrifuged solution was collected, and the amount of EGCG loaded in liposomes was estimated by comparing its absorption value at 274 nm to that of the calibration curve. The encapsulation efficiency of EGCG in liposomes was calculated by Equations (2). Surface morphology and liposome structure were observed with a negative staining transmission electron microscope (TEM) using phosphotungstic acid (PTA) dye because liposomes are transparent and colorless.

Encapsulat ion efficiency (%) = -Total amount of encapsulat ed EGCG Total amont of EGCG in supernatan t × 100% (2)

In this study, the concentration of EGCG in EGCG-loaded liposomes was calculated from 43.6 mM (the EGCG stock solution) × 0.5 mL/1 mL × corresponding encapsulation efficiency × the dilution factor in use. All the concentrations describing the EGCG-loaded liposomes in this study denoted the concentration of EGCG in EGCG-loaded liposomes.
