Zeta potential particle size analyzer

The hydrodynamic diameters and zeta potential of PL-Lip and PL-SNP were assessed using a Zeta Potential/Particle Size analyzer (Malvern Instruments, Malvern, UK). The morphological characteristics of PL-Lip and PL-SNP were observed under TEM using a JEOL model JEM-1400 Plus at an acceleration voltage of 100 kV. The sample was placed on a copper grid and dried under the lamp, then subjected to negative dyeing with phosphotungstic acid solution. For the estimation of encapsulation efficiency, PEGylated liposome solution (4 mg·mL⁻¹) was filtered to remove the unentrapped drug. The drug concentration was measured with HPLC method described in Supplemental material. The encapsulation rate (EL, %) was calculated according to the following formula:
$$\text{EL}\left(\%\right)=\left(X_{\text{1}}/X_{\text{2}}\right)\times \text{\hspace{0.17em}1}00\%.$$
where X₁ represented the weights of total prodrugs in PEGylated liposome after filtration, and X₂ stood for the initial prodrug added for encapsulation.

The micromorphology and elemental content of S-AgNP NPs were analyzed by transmission electron microscopy (FE-TEM) and energy-dispersive X-ray spectroscopy (EDS) (JEOL-JSM, Akishima, Japan). The particle size distributions and potentials of the nanoparticles were determined by a zeta potential particle size analyzer (Malvern PANalytical, Worcestershire, UK). The crystallinity of the starch, S-AgNP NPs, and AgNP NPs were determined using X-ray powder diffraction (XRD, X’pert-pro MPD-PANalytical, Worcestershire, UK). The functional characteristics of the nanoparticles were detected by Fourier-transform infrared spectroscopy (FTIR, PerkinElmer Paragon 500, Waltham, MA, USA). For the XRD and FTIR analysis, the starch, S-AgNP NPs, and AgNP NPs were analyzed after sufficient drying and grinding into powder. The silver content of S-AgNP NPs was analyzed using ICP-MS (PerkinElmer (NextION 300D), Waltham, MA, USA); in brief, 10 mg of sample was dissolved in 150 μL of HNO₃ and 350 μL of HCl, and after 3 h of full acid digestion, 20 μL was diluted in 10 mL of 0.2% HNO₃ solution. The silver and iron contents of AgNP NPs were determined according to standard calibration curves for silver and iron (1, 2.5, 5, 10, 25, 50, 100 μg/L) [16 (link)].