Zetasizer nano s equipment

The optical characterization of M-SPIONs dispersed in aqueous medium was performed at 50 µg Fe/mL using an RF-6000 spectrofluorophotometer (Shimadzu, Kyoto, Japan) to acquire the spectrum with excitation in the wavelength range from 520 to 800 nm and emission from 550 to 780 nm.
The polydispersion of hydrodynamic diameter (HD), temporal stability of HD and zeta potential of M-SPIONs (50 µg Fe/mL) were measured using dynamic light scattering (DLS) with Zetasizer Nano S equipment (Malvern, Reino Unido). The HD distribution curve was obtained using an angle of 173 degrees with 15 measurements in 5 s, maintaining a constant temperature at 37 °C. M-SPION HD stability analysis was performed in cell culture medium (DMEM +10% FBS) for 20 h. The zeta potential measurements (surface charge) were performed in the pH range from 7 to 9.

An AgNO₃ solution of 1 × 10⁻³ M concentration was prepared by dissolving 18 mg of the salt in 100 mL of distilled water; the solution was stirred until complete dissolution; then, it was adjusted to pH 8 with a 1 M solution of NaOH. The solution was heated at 85 °C under continuous stirring for 10 min, during this process, 1 mL of sodium citrate solution (1% w/v) was added. The solution was kept on the heat for one hour at 85 °C; until the solution acquired a brownish color [44 (link)]. After that, it was cooled at room temperature, obtaining a suspension of 18 µg/mL. The absorbance of the colloidal system was determined by UV-vis spectroscopy in a Specord 200 plus spectrophotometer (Analytik Jena AG, Jena, Germany).
AgNP size was determined using Malvern Zetasizer Nano S equipment and DTS (nano) software from Malvern instruments, Madrid, Spain. Diluted samples were sonicated for 10 min to deagglomerate the nanoparticles; then, the suspension was placed in disposable polystyrene cuvettes, and the scattering intensity was measured at 25 °C. Water was used as the dispersant. The analysis was carried out by triplicate, and several records were performed in each analysis.