Vista ax spectrometer

Living Hydra exposed to Rhodamine-labeled SiO₂NPs (25 nM) were observed under fluorescent microscopy after 24 h of treatment.
To estimate the intracellular Silicon, replicates of 150 Hydra were either exposed to 10 and 25 nM SiO₂NPs (experiment) or maintained in culture solution (control) for 24 h. The incubations were carried out in 10 mL. Samples were washed and digested by the addition of HCl/HNO₃ 3:1 (v/v) solution. The incubation media were recovered and digested as for samples. The resulting solutions were directly analyzed to evaluate the Si concentration through elemental analysis that was carried out by inductively coupled plasma atomic emission spectroscopy (ICP-AES) with a Varian Vista AX spectrometer.

First, 10⁵ MCF-7 cells were seeded in 1 mL of medium in a six well plate. After 24 h at 37 °C, the medium was replaced with fresh DMEM containing the TiO₂NPs (25 and 50 µg/mL). After 24 and 48 h of exposure at 37 °C, DMEM was removed and the cells washed several times with Phosphate Buffered Saline (PBS) (pH 7.4). Cells were trypsinized and counted using an automatic cell counting chamber. Next, 360,000 cells were suspended in 200 µL of milliQ, treated with HCl/HNO₃ 3:1 (v/v) and diluted to 5 mL: the obtained solution was analyzed to evaluate Ti content. Elemental analysis was carried out by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) with a Varian Vista AX spectrometer.

TPR experiments (ca. 45 mg of sample) were performed on a Micromeritics Autochem II within a temperature range of 60–900 °C (10 °C/min heating rate) under flowing (50 mL/min) 10%H₂/Ar. The specific surface areas of the samples were obtained by adsorption–desorption of N₂ at 77 K on a Micromeritics ASAP 2020 following the multi-point Brunauer–Emmett–Teller (BET) method. The samples were previously degassed at 300 °C under vacuum for 100 min. Powder XRD analyses were carried out on a Rigaku UltimaIV diffractometer employing CuKα radiation and a scanning rate of 2°/min. SEM observations were carried out on a Hitachi S5200 microscope, and samples were used without any further modification. Inductively coupled plasma atomic emission spectroscopy (ICP–AES) was used to determine the actual oxide content of the different samples. This measurement was made on a Varian Vista AX spectrometer, and samples were previously dissolved in 5 mL of aqua regia (HNO₃:HCl, 1:3 in volume).