Malvern zetasizer nano zs system

Dynamic light scattering (DLS) and zeta potential analyses were performed at 25 °C using a Malvern Zetasizer NanoZS system (Malvern Instruments Ltd., UK.). HA-MSA2 was dissolved in PBS, pH 7.4 (2 mg/mL), and was analyzed at a fixed angle of 173° at 25 °C with a red laser (λ = 633 nm). The zeta potential was measured by dissolving HA-MSA2 (2 mg/mL) in KCl (1 mM). All measurements were performed in triplicate.

The Malvern Zeta sizer Nano ZS system (Malvern Instruments Ltd., Worcestershire, UK) was used to assess the zeta potential of AuNPs and CS-AuNPs at 25 °C. The XRD patterns of AuNPs and CS-AuNPs were obtained with a Diano X-ray diffractometer and a Philips X-ray diffractometer at 45 kV, 4^◦/min, and a scanning range of 5^◦ ~ 80^◦. The UV-visible absorption spectra of AuNPs and CS-AuNPs were measured at ambient temperature using a spectrophotometer (JENWAY 6305 Stone, UK) within the 300–800 nm wavelength range.

DiO/DiI-loaded PLGA NPs were prepared by anti-solvent and flash nanoprecipitation method based on our previous publication⁸ (link). DiO/DiI and PLGA (5 mg/mL) were dissolved in DMF as organic phase, and stabilizer tween 80 (0.1%, 1 mg/mL) dissolved in diluted water was regarded as aqueous phase. Organic phase was fast injected by syringe into aqueous phase (1:9, v/v) with constant stirring on magnetic stirrer. Sizes of DiO/DiI-loaded PLGA NPs were changed by controlling the stirring speed. After finishing the preparation, the organic solvent was removed by using ultrafiltration device with a centrifugation speed at 4000 rpm (Heraeus™ Multifuge™ X3R, Thermo Fisher Scientific, Waltham, MA, USA) for 10 min. Triplicated centrifugations were made to ensure the organic solvent was totally removed. Then the prepared NPs were diluted in Milli-Q water, and the particle size, polydispersity index (PDI) and zeta potential were measured using a Malvern Zetasizer Nano-ZS system (Malvern Instruments, Worcestershire, WR, UK). Triplicated measurements were conducted for each sample. Two prepared NPs were diluted by water and dropped onto surface of a specific copper mesh and dried overnight. Finally, prepared samples were photographed using a transmission electron microscope (TEM, JEM-2100F, Tokyo, Japan).