Malvern zetasizer nano s

As stabilizing agents, surface-modified silica nanoparticles or Tween 80 surfactant (Polysorbate80, Acros Organics, New Jersey, NJ, USA) were used. The concentration of stabilizing agents and chamomile essential oil (bluish Matricaria chamomilla oil, Aromax Ltd., Budapest, Hungary) was kept constant for all experiments, the values were 1 mg/mL and 100 µg/mL, respectively. The first step of the emulsification process was sonication for 2 minutes (Bandelin Sonorex RK 52H, BANDELINelectronic GmbH & Co. KG, Germany), then emulsification using UltraTurrax (IKA Werke T-25 basic, IKA®-Werke GmbH & Co. KG, Germany) for 5 min at 21,000 rpm. To compare the different formulations, an ethanolic solution was also prepared; chamomile essential oil was added to absolute ethanol at 100 µg/mL concentration, and the solution was sonicated for 5 min.
The stability of Pickering emulsion was studied from periodical droplet size determination using DLS measurements (Malvern Zetasizer Nano S, Malvern Panalytical Ltd, Worcester, UK).

The particle size, size distribution, PDI, and zeta-potentials were measured by a Malvern Zetasizer (Nano S; Malvern Instruments Ltd., UK). To check pH stability, the particles were incubated in pH 4.0, pH 5, pH 6.5, or pH 7.4 PBS solutions. All measurements were performed in triplicate.
To observe the structure of GC-DOX/RAPA ω-liposomes, an aliquot of the liposome solution (10 μL of 1 mg/mL lipid) was placed on a carbon-coated 400 mesh copper grid for 10 min. The solution was removed by gentle tapping, washed twice, negative-stained, and then dried. The prepared samples were observed with an electron microscope (JEOL-2100F; JEOL Ltd., Japan).

The samples were transferred to quartz cuvettes (3 mm path length). Dynamic light scattering (DLS) measurements were performed using a Malvern Zetasizer Nano-S (Malvern Panalytical, Malvern, UK), software version 7.13, with set angle 173°and temperature 20 °C. Data analysis was done using the Malvern Zetasizer software to obtain the apparent intensity-based and number-based size distributions. Using the Stokes–Einstein equation [44 (link),45 (link)] assuming spherical particles, the apparent hydrodynamic radius was calculated. The number-based size distributions calculated by the software assuming, from Raleigh’s approximation [32 (link)], that the intensity of scattering by a particle is proportional to the sixth power of its radius.

Multilamellar vesicles (MLVs) were prepared by dry film formation and hydration, as described in [65 (link),68 (link)]. Briefly, MLVs were formed by evaporating the required amounts of the lipids dissolved in chloroform/methanol 3/1 (v/v) to dryness under a stream of nitrogen. Solvent traces were subsequently removed by evacuation under reduced pressure. MLVs were obtained by hydrating the dry lipid films in buffer A (5 mM Tris-HCl, pH 7.4, 150 mM NaCl, and 150 µM of CaCl₂) and allowing them to swell for 1 h at a temperature above the gel-to-liquid phase transition temperature of lipid mixtures. Large unilamellar vesicles (LUVs) were prepared by extrusion of MLVs through a 100 nm pore-sized polycarbonate membrane. The mean diameter of the resulting LUVs was 130 ± 3 nm, as determined by dynamic light scattering using a Malvern Zetasizer Nano S (Malvern Instruments Ltd., Malvern, UK). For differential scanning calorimetry, Re-LPS was suspended directly in buffer A and allowed to swell for 1 h at 45 °C, as previously described [30 (link)]. The final lipid and Re-LPS concentrations of both multilamellar and unilamellar vesicles were assessed by phosphorus determination and quantification of 2-keto-3-deoxyoctulosonic acid, respectively.

Gold concentration in GNR solutions was determined before and after the ligand exchange reaction by atomic absorption spectroscopy (SpectraAA 100 Varian, Agilent Technologies Inc., Santa Clara, CA, USA) using air-acetylene flame for atomization. Standard solutions at 1, 2, 5, and 10 mg L⁻¹ of atomic gold were analyzed to obtain a calibration curve. GNRs were previously digested with aqua regia at room temperature and diluted with water to achieve a gold concentration that could fit in the calibration curve.
VIS-NIR spectroscopy was performed with a Cary5000 double-beam spectrometer (Agilent Technologies Inc., Santa Clara, CA, USA) on 500 μM GNRs samples using water as a reference and scanning from 400 to 1100 nm.
Transmission Electron Microscopy was performed with an FEI TECNAI F20 microscope (Thermo Fisher Scientific, Waltham, MA, USA) operating at 200 keV after drop-casting a perforated carbon film supported by a copper grid with an aqueous dispersion of GNRs. The preparation was then dried at 100 °C.
Dynamic light scattering measurements were performed on a Malvern Zetasizer-Nano-S (Malvern Panalytical, Malvern, UK) working with a 532 nm laser beam. ζ potential measurements were conducted in DTS1060C-Clear (Malvern Panalytical, Malvern, UK) disposable zeta cells at 25 °C.