Disposablezeta cells

Both electrophoretic and DLS
measurements were carried out with a Zetasizer Nano Instrument (Malvern)
equipped with a 4 mW He–Ne laser (633 nm wavelength). The electrophoretic
mobilities (u) were converted to ζ-potentials
(ζ) by the Smoluchowski equation as^{44 (link)} where ε is the dielectric constant of
the medium (78.5 at the respective temperature), η is the dynamic
viscosity of water (8.9 × 10^–4 Pa s), and ε₀ is the dielectric permittivity of vacuum (8.9 × 10^–12 F/m). For the determination of the ζ-potentials,
2 mL of dispersions were prepared by diluting the appropriate volume
of particle dispersions or dispersions of PE-coated BNNS particles
with an appropriate amount of water and salt solutions to obtain a
final particle concentration of 5 mg/L. The samples were allowed to
rest for 2 h at room temperature before each measurement, and the
equilibration time in the device was 1 min. The reported ζ-potential
values were the average of three individual measurements, and the
average error was about 5%. The experiments were performed in disposable
Zeta cells (Malvern).

Dynamic light scattering (DLS) measurements were performed on a Malvern Zetasizer Nano (Malvern, UK) in backscatter mode. Analyses were performed on nanoparticle solutions with concentration of 10 mg/mL or 3.7 mg/mL, using either disposable microcuvettes or disposable zeta cells (Malvern). The cell positioning factor was set to 0.83 mm and attenuator values of five or nine were auto-optimized as a function of nanoparticle concentration.