Dts1070 capillary cells

Z–potential measurements were made at 25 °C with a Zeta Sizer instrument (Nano-ZS, Malvern Instruments). Samples were introduced into DTS1070 capillary cells (Malvern Panalytical) with the diffusion barrier technique, while data were analyzed with Zetasizer Software. Phase Analysis Light Scattering (PALS) was used to determine the average zeta potential of vesicles dispersed in PBS. A fast measurement process (fast field reversal mode: FFR) was selected, because of the high ionic strength of the dispersing media (PBS). Sizes were also measured before and after the zeta potential measurements to check the sample had not changed because of the measurement.

A Zetasizer Nano ZS (Malvern Instruments, Herrenberg, Germany) equipped with the Zetasizer v7.12 software (Malvern Instruments Ltd, Worcestershire, UK) was used to analyze the HD, PDI and ZP of the NPs. Photon correlation spectroscopy was used to measure HD and PDI of an aqueous NP dispersion in ZEN 0112 cuvettes (Brand, Wertheim, Germany) at 633 nm and 25 °C under a scattering angle of 173 °C. Five runs per sample were used to calculate the mean values ± SD of at least four independent NP preparations. To determine the ZP the electrophoretic mobility was measured in DTS 1070 capillary cells (Malvern Instruments) at 25 °C. A refractive index of 1.33 and a viscosity of 0.88 mPa‧s were used for calculations. At least four independent NP preparations with three runs per sample were analyzed and represented as mean values ± SD (intensity weighted distribution).

The zeta potential of the formulations was evaluated based on our previously reported method (Kolawole et al., 2018 (link)). Briefly, folded DTS-1070 capillary cells (Malvern, UK) were filled with 1% w/v chitosan solutions or CHIGP formulations (sol form) and their zeta-potential values were determined at 25 and 37 °C using Zetasizer Nano-ZS (Malvern Instruments, UK). The samples were studied after 1 in 20 dilution to 0.05% w/v chitosan: 0.6% w/v β-glycerophosphate using ultrapure water. The instrument was set to operate at an absorbance of 0.01 and refractive index of 1.59. Measurements were conducted in triplicates with 50 sub-runs per reading.