Orius sc600a ccd camera

TEM was used to analyse CB particle size, shape, morphology, crystallinity, and purity. A drop of diluted material (50 μg/mL in double distilled H₂O) was drop-cast on a copper TEM grid coated with a continuous carbon film (Agar Scientific, Stansted, UK) and left to air dry overnight, in a sterile environment. TEM analysis was undertaken with a FEI Talos F200x G2 TEM (Thermo Fisher Scientific, Altrincham, UK), operating at 200 kV and fitted with a high-angle annular dark field (HAADF) detector, a Gatan Orius SC600A CCD camera, and an Oxford Instruments 80 mm² silicon drift energy-dispersive X-ray (EDX) spectrometer. Images were taken from 20 areas at magnifications between ×7000 and ×40,000 with a dwell time of 10 μs.

Samples of selenite-amended culture (1.5 mL) were pelleted by centrifugation (11,000×g; 10 min; room temperature) and washed with 0.1 M sodium phosphate buffer (pH 7.4). The specimens were then fixed in 3% glutaraldehyde in the same buffer overnight at room temperature and washed again in the same buffer. Secondary fixation was carried out in 1% w/v aqueous osmium tetroxide for 1 h at room temperature followed by the same wash step. Fixed cells were dehydrated through a graded series of ethanol dehydration steps (75, 95 and 100% v/v) and then placed in a 50/50 (v/v) mixture of 100% ethanol and 100% hexamethyldisilazane followed by 100% hexamethyldisilazane. The specimens were then allowed to air dry overnight. A small sample of the fixed sample was crushed and dispersed in methanol, with a drop placed on a holey carbon-coated copper grid (Agar Scientific). The samples were examined in an FEI Tecnai F20 field emission gun (FEG)-TEM operating at 200 kV and fitted with a Gatan Orius SC600A CCD camera, an Oxford Instruments X-Max SDD EDX detector and a high-angle annular dark-field (HAADF) scanning TEM (STEM) detector.

For cellular uptake studies, samples were prepared as previously described (Hondow et al., 2011 (link)). Briefly, the treated cells were harvested and placed in 2.5% glutaraldehyde fixative. Thin sections (>70 nm) were cut from the polymerized block using an ultra-microtome (Leica Microsystems, EM UC7). TEM was conducted as previously described (Hondow et al., 2011 (link)) on a FEI Tecnai F20 operating at 200 kV and fitted with a Gatan Orius SC600A CCD camera for imaging and an Oxford Instruments X-Max SD detector for EDX analysis.