Phosphotungstic acid solution

The average hydrodynamic diameter and the size distribution of nanomicelles (polydispersity index, PdI) were determined by dynamic light scattering (DLS, Zsizer Nanoseries ZS90, Malvern Instrument, Worcestershire, UK) at 25 °C and at a scattering angle of 90°. The zeta potential was evaluated measuring the electrophoretic mobility of nanomicelles by electrophoretic light scattering technique (ELS) employing the same instrument. The results were expressed as the average of three measurements.
The morphology of PNM and MNM was investigated by means of transmission electron microscopy (TEM, Jeol 1010, Tokyo, Japan). Before the analyses, the samples were placed onto a 200-mesh copper grid coated with carbon and negative stained with 1% w/v phosphotungstic acid solution (Electron Microscopy Sciences, Hatfield, PA, USA) [64 (link)].

The morphological characterization of nanoformulations was performed by TEM CM12 (Philips, The Netherlands) equipped with an OLYMPUS Megaview G2 camera at accelerating voltage of 80 keV. Before the analyses, the samples were diluted in distilled water and placed onto a 200-mesh copper grid coated with carbon. Most of the sample was blotted from the grid with filter paper to form a thin film. After the adhesion of formulation, 5 μL of phosphotungstic acid solution (1% w/v in sterile water, Electron Microscopy Sciences, Hatfield, PA, USA) were dropped onto the grid as a staining medium and the excess solution was removed with filter paper. Samples were dried for 3 min, after which they were examined with the electron microscope [32 (link)].