Em ace 600 high vacuum sputterer

The cells on the microsieves were rinsed twice with PBS at 37 °C after 24 h cultivation (an analogous process to that with the LIVE/DEADTM Viability/Cytotoxicity Kit). They were then fixed for 30 min at room temperature in a mixture of 4% formaldehyde and 0.4% glutaraldehyde and PBS physiological saline solution. After preservation, the reagent residues were removed by rinsing the micro sieves with the cells twice with demineralized water.
Due to the lack of cell conductivity, the samples were dried in a Vacucell 22 L vacuum dryer (BMT Medical Technology s.r.o., Brno-Zábrdovice, Czech Republic) and then a 5.12 nm gold layer was deposited on their surface using an EM ACE 600 high-vacuum sputterer (Leica Microsystems, Wetzlar, Germany). To ensure an even spray, the table was rotated at an angle of 120° during the process.
Studies of cancer cell lines separated on Au, Au + GO, Ni and Ni + GO microsieves were performed using scanning electro-new microscopy (SEM) (Quanta 250 FEG SEM, FEI, Hillsboro, OR, USA).
The SEM image was obtained using a backscattered detector (ETD-BSE, FEI, Hillsboro, OR, USA) with an accelerating voltage of 5 kV for GO and 10 kV for cancer cells (all variants).

A scanning electron microscopy (SEM) analysis of bacterial samples was performed by means of an FEI Quanta 200 electron microscope (FEI Co., Hillsboro, OR, USA). The bacteria samples were rinsed in PBS (0.01 M, pH 7.2; P4417, Sigma-Aldrich, Poznań, Poland) and then fixed in 2.5% glutaraldehyde (G5882, Sigma) for 1 h, washed twice with 0.1 M PBS (0.01 M, pH 7.2; P4417, Sigma), and placed on aluminum SEM stubs. The SEM stubs were kept in a moist atmosphere for 1 h, washed with PBS (0.01 M, pH 7.2; P4417, Sigma), postfixed in 1% osmium tetroxide (75632, Sigma) for 1 h, rinsed in distilled water, and dehydrated in graded ethanol. After critical point drying with liquid CO₂ in a vacuum apparatus (Polaron CPD 7501, Quorum Technologies, Newhaven, East Sussex, UK) and coating with a 5.12 nm gold layer gold using an EM ACE 600 high-vacuum sputterer (Leica Microsystems, Wetzlar, Ger-many), the samples were inspected by SEM at 5 KeV (Quanta 250 FEG SEM, FEI, Hillsboro, OR, USA).