2.3. Liposome Characterization

Liposome size and size distribution were measured using Dynamic Light Scattering. This technique traces Brownian motion and relates this motion to particle size. The equipment used was the Zetasizer Nano S90 (Malvern, Worcestershire, UK). The equipment utilizes a He/Ne laser with emission at 632.8 nm, a power of 4 mW, and a 90° scattering detector. Measurements were performed at a stable temperature of 25 °C. Five hundred microliters of each sample was placed in a low-volume disposable cuvette. The average hydrodynamic diameter (Z-Average) and Polydispersity Index (PDI) of at least three independent measurements were recorded per sample. Liposomes collected from the outlet were further diluted for a final lipid concentration of 0.04 mg/mL. This concentration proved to yield high-quality measurement results. Liposome zeta potential was measured by placing each sample in a disposable cuvette (1850 µL). The measurements were performed using the ZetaPlus (Brookhaven Instrument Corp., Holtsville, NY, USA) at a stable temperature of 25 °C and a pH = 7.00. The measurement results were calculated based on the electrophoretic mobility of suspended particles under an electrical changing field. Zeta potential average is a result of 2 stable cycles and ten measurement repetitions.