Particle size analyzer

PDAPEI/pDNA complexes were prepared at different weight/weight (w/w) ratios of 1–50. First, PDAPEI was dissolved with deionized water (2 mg/ml) and pDNA (2 mg/ml). Then, the PDAPEI solution was diluted to different concentrations and added rapidly into the pDNA solution. Next, the solutions were incubated at room temperature for 30 min, and PEI/pDNA complexes and naked pDNA were simultaneously prepared as controls.
Agarose gel electrophoresis assay was used to evaluate the condensation ability of PDAPEI/pDNA complexes at different w/w. The particle size and zeta potential of PDAPEI/pDNA complexes were measured using a particle size analyzer (Brookhaven Instruments) and a zeta potential analyzer (Zetasizer Nano, Malvern Instruments) at different w/w ratios. Zeta potential across a range of pH (5.4, 6.4, 7.4, 8.4, 9.4) was measured to analysis its stability and degradation. The morphology of the PDAPEI/pDNA complexes was observed by Transmission electron microscopy (JEOL JEM 2010 system).

The particle sizes of the HANPs and AgNPs used in this study were measured using a particle-size analyzer (Brookhaven Instruments). In addition, an FEI Sirion 200 scanning electron microscope (SEM; United States) was used to obtain images of HANP, AgNP, PM, SR-PM, SR-PM-Ag, and SR-PM-Ag-HA samples. All specimens were coated by gold evaporation at 5 keV under an argon atmosphere before SEM tests.

The hydrodynamic diameter and PDI were measured using a Particle Size Analyzer (Brookhaven Instruments Corporation, Software: Particle Sizing v.5 Brookhaven Instruments, Holtsville, New York, USA). The zeta potential of the developed LNPs was determined using the Zeta Potential Analyzer (ZetaPALS, Brookhaven Instruments Corporation, Software: PALS Zeta Potential Analyzer v.5 Brookhaven Instruments, Holtsville, New York, USA). The system operated with an incidence light angle of 90˚, at room temperature. Prior to the measurements, the LNPs were diluted (1:100) in type I water.
The morphology of the produced LNPs was assessed by TEM. For this purpose, the formulations were diluted (1:100) in type I water. Then, 10 µL of the diluted LNPs were placed onto a copper-mesh grid for 2 min. The excess of LNPs was then removed, and 10 µL of 0.75% (w/v) uranyl acetate solution were added to the grid for 30 s (negative staining). The samples were observed in a JEM-1400 transmission electron microscope (JEOL Ltd., Tokyo, Japan) with an acceleration voltage of 80 kV.

The mean particle size and polydispersity index (PdI) were evaluated using dynamic light scattering (DLS) at 659 nm, with a detection angle of 90°, on a particle size analyzer (Brookhaven Instruments, Long Island, NY, USA), at 25 °C. The zeta potential measurements were performed on the same equipment, applying a field strength applied around 5.9 V cm⁻¹ and using Zeta Plus^® software Particle Sizing version 3.95. Samples were diluted 1:50 (v/v) with purified water using ten measurements in triplicate. Data were expressed as mean ± standard deviation (SD).

The particle size distribution and polydispersity index (PDI) of the liposome particles was determined at 25˚C by dynamic light scattering (DLS) using a ZetaPALS zeta potential and particle size analyzer (Brookhaven Instruments, Holtsville, NY, USA). Each parameter was measured three times, after which we calculated average values and standard deviations. L-DOX morphology was investigated by cryogenic transmission electron microscopy (Cryo-TEM, FEI Tecnai 20, type Sphera, Hillsboro, OR, USA).

The particle size and zeta potential of PDAPEI/pDNA polyplexes were measured at different w/w ratios by Particle-Size Analyzer (Brookhaven Instruments) and Zeta Potential Analyzer (Zetasizer Nano, Malvern Instruments), respectively at 25 °C. The morphology of PDAPEI/pDNA polyplexes was imaged by transmission electron microscopy (JEOL JEM 2010 system) at the w/w ratio of 2.

PVO was synthesized from the reaction of oxalyl chloride, and acid-cleavable vanillin derivative as previously reported [23 (link)]. In brief, and acid-cleavable vanillin derivative (3.941 mmol) was placed in a flask containing 25 mL dried dichloromethane and pyridine (9.8 mmol). The flask was placed in ice bath and added with oxalyl chloride (3.941 mmol). The reaction was continued for 6 h at room temperature. PVO was obtained from extraction using dichloromethane/water and precipitated in cold hexane. After purification, the chemical structure of PVO was verified by NMR. PVO nanoparticles were prepared by a single emulsion method as previously reported [23 (link)]. Indocyanine green (ICG)-loaded PVO nanoparticles were also prepared for fluorescence imaging. Unloaded ICG was removed by centrifugation twice. The PVO nanoparticles suspended in water were characterized using a scanning electron microscopy (SUPRA40VP, Carl Zeiss, Jena, Germany) and particle size analyzer (Brookhaven Instruments, Holtsville, NY, USA). UV-vis absorption of the ICG-loaded PVO nanoparticles was investigated using a spectrometer (S-3100, Scinco, Seoul, Korea).