Polaron cpd 7501 critical point dryer

Scanning electron microscopy (SEM) observations of the U87 or U118 glioblastoma cells were done using a Quanta 200 microscope (FEI, Hillsboro, OR, USA). U87 or U118 glioblastoma cells were seeded in 35 mm diameter Petri dishes (1×10⁵ cells per well). After 24 h, ND, NG, or nGO were introduced to the cells at a concentration of 20 μg/mL. Preparation of the cells for SEM observation was done after 24 h of exposure to nanoparticles in accordance with the protocol of Heckman et al.20 (link) Cells were fixed with 2.5% glutaraldehyde in phosphate-buffered saline (PBS) 7.2 pH, contrasted with 1% osmium tetroxide (Sigma-Aldrich Co., St Louis, MO, USA) and 1% carbohydrazide (Sigma-Aldrich). Subsequently, cells were dehydrated in increasing concentrations of hexylene glycol (Sigma-Aldrich). Drying was performed using a Polaron CPD 7501 critical point dryer (Quorum Technologies, Laughton, UK).

Details of cell morphology were evaluated using scanning electron microscopy (SEM: Zeiss, Ultra Plus, Oberkochen, Germany). HS-5, HepG2 and C3A cells were seeded on 6-well plates coated with nanofilm of C₆₀ dots. SEM observations of cells were completed with a Quanta 200 electron microscope (FEI, Hillsboro, OR, USA). Cells were prepared for SEM observation after 7 days of exposure to the C₆₀ nanofilms. The cells were rinsed in phosphate-buffered saline (PBS, pH 7.2), then fixed in 2.5% glutaraldehyde (G5882, Sigma-Aldrich, St. Louis, MO, USA) for 30 mins. Cells were contrasted and dehydrated according to Wierzbicki et al.47 (link) Samples were placed on aluminum SEM stubs. Subsequently, cells were dehydrated in increasing concentrations of hexylene glycol (Sigma-Aldrich, St. Louis, MO, USA). Drying was performed with a Polaron CPD 7501 critical point dryer (Quorum Technologies, Laughton, UK).