Zetasizer nano apparatus

Measurements of hydrodynamic diameter were performed on a Malvern Zetasizer Nano apparatus with backward diffusion of laser light at a wavelength of 633 nm (173°) in quartz cuvettes at 25 °C. Before the measurement, the conjugate was diluted with 10 mM phosphate buffer at pH 7.2, resulting in a final carrier concentration in the test sample of 11.11 μM. The final result of the measurements was obtained by averaging 6–10 independent measurements. The applied coefficient of analyte refraction was 1.520. Buffer viscosity was calculated using Zetasizer 7.11 software (the value was 1.051 cP). Data from hydrodynamic diameter measurements were also analysed using Zetasizer 7.11 software.
Furthermore, measurements of zeta potential were performed on a Malvern Zetasizer Nano apparatus with backward diffusion of laser light at a wavelength of 633 nm (173°) in zeta potential-measuring cuvettes (ZEN1010, Malvern). Before the measurement, the conjugate was diluted with Milli-Q water to obtain a final carrier concentration in the test sample of 11.11 μM. The final result of the measurements was obtained by averaging 10–20 independent measurements. Data from zeta potential measurements were analysed using Zetasizer 7.11 software.

The aqueous solubility of
the metal complexes was assessed by dynamic light scattering. The
metal complexes were dissolved in DMSO at a concentration of 10 mM.
The stock solutions were diluted with phosphate-buffered saline (PBS)
buffer to a dilution of 2% DMSO and a compound concentration of 200
μM. The resulting solutions were analyzed by dynamic light scattering
(DLS) using a Malvern Instruments Zetasizer Nano apparatus. All metal
complex solutions remained clear and did not show any precipitation.
Zinc oxide, which readily precipitates in an aqueous solution, was
used as a positive control.

Electrokinetic measurements were obtained at 25°C in a PBS (pH 7.2) between each functionalization step using a Zetasizer Nano apparatus (Malvern Instruments, United Kingdom). The zeta potential was calculated: on the basis of the Schmolukowski model.