Formvar on 3 mm 200 mesh cu grids

The effect of the interaction between the nanoparticles used and the bacteria cells was evaluated by transmission electron microscope JEM-1220 (JEOL, Tokyo, Japan), operated at a voltage of 80 keV. The overnight bacteria suspension was adjusted to 1.5 × 10⁸ cells/mL and treated with AgNPs, GO and GO-Ag. Droplets of each sample were placed onto TEM grids (Formvar on 3 mm 200 Mesh Cu Grids, Agar Scientific, Stansted, UK), and the samples were observed immediately.

The morphology of the nanoparticles obtained from Nano-Tech Poland was determined by analyzing transmission electron microscopy (TEM) images. The nanoparticles were viewed using a JEM-2000EX transmission electron microscope (JEOL). The nanoparticles’ hydrocolloid was sonicated for two minutes and then applied to a molding TEM grids (Formvar on 3 mm 200 mesh Cu grids, Agar Scientific, Stansted, UK) and left to dry for 24 h. Images of the nanoparticles were taken at a voltage of 80 keV.

Tumor tissues were cut immediately after resection into pieces of about 1.5 mm³ and fixed in a 2.5% glutaraldehyde solution (Sigma-Aldrich) in 0.1 M PBS (pH 7) overnight. The samples were washed in the PBS and transferred to a 1% osmium tetroxide solution (Sigma-Aldrich) in 0.1 M PBS (pH 7) for 1 h, then washed in distilled water, dehydrated in ethanol gradients, and impregnated with epoxy embedding resin (Fluka Epoxy Embedding Medium Kit; Sigma-Aldrich). After 24 h, the samples were embedded in the same resin and baked for 24 h at 36 °C, then transferred to a 60 °C incubator and baked for a further 24 h. The blocks were cut into ultrathin sections (50 nm) using an ultramicrotome (Ultratome III; LKB Products, Vienna, Austria) and transferred onto TEM grids (Formvar on 3 mm 200 Mesh Cu Grids, Agar Scientific, Stansted, UK). Sections were contrasted using uranyl acetate dihydrate (Sigma-Aldrich) and lead (II) citrate tribasic trihydrate (Sigma-Aldrich), and examined by TEM.