Icp ms

The mice were sacrificed at 24 h (n = 3) after iv-injection of Cu(I)-GSH and Cu(II)-GSSG complexes, respectively. The collected organs were weighed and the copper contents were obtained from the ICP-MS (Fisher Scientific, Asheville, NC, USA).

For the U(VI) uptake and release assay, exponentially growing NRK-52E cells were cultured for 24 h, and then 12.4 μM U(VI) and 320.0 μM of chelating agents were added to the experimental group, while only 12.4 μM U(VI) was added to the control group. After 48 h cultured with U(VI) and chelators, the cell cultures were washed with PBS, trypsinized, counted, and lysed. For the U(VI) release assay, the NRK-52E cells were cultured for 24 h, followed by the addition of 2.0 mL culture medium contained 12.4 μM U(VI) into the experimental and control groups, and then the culture medium contains uranium was discarded 24 h later. Then 320.0 μM of chelating agent was added to the experimental group, while only culture medium was added to the control group. After 24 h the addition of chelating agents, the cell cultures were washed with PBS, trypsinized, counted, and lysed. Each group was performed with three parallel samples. The U(VI) content of the cells were analyzed by ICP-MS (Thermo Scientific) and converted to ng per 10⁶ cells (Supplementary Table 5 and 6).

The quantification of major and trace elements was performed using inductively coupled plasma optical mass spectrometry (ICP-MS, Thermo Fischer Scientific, Cambridge, UK). The conditions for ICP-MS analysis were described in our previous study [39 (link)].

To investigate the in vivo dynamics of PTX-loaded MSNs, the intravenous kinetics of the particles were studied in female SD rats weighing 200 ± 20 g. Twelve rats were randomly divided into 4 groups (n = 3) and administered with PTX-loaded MSN-S, MSN-R, MSN-H, and free PTX solution (10 mg PTX equivalent/kg, 1 mL) via tail vein injection. Blood samples (300 μL) were collected from the rats’ eye sockets at 5, 15, and 30 min and 1, 2, 4, 8, 12, 24, and 48 h post-injection into heparinized tubes. Subsequently, 100 μL of the blood sample was added to 600 μL of concentrated nitric acid, and after complete digestion, it was diluted to 7 mL with pure water. The silicon element content in the blood was quantified using ICP-MS (Thermo Fisher Scientific, Waltham, MA, USA) to quantify the nanoparticles in the blood [44 (link)].
For the quantification of PTX in the blood, 10 μL of 100 μg/mL norethindrone was added as an internal standard, and 200 μL of the blood sample was extracted with 2.5 mL of methanol. The mixture was vortexed for 2 min and then centrifuged at 4000 rpm for 10 min, and 2 mL of the supernatant was taken and dried by nitrogen. The residue was redissolved in 100 μL of acetonitrile. PTX concentration was determined by UPLC. Pharmacokinetic parameters were calculated using DAS 2.0 (China National Medical Products Administration, Beijing, China) [45 (link)].

Ground finger millet grain samples were acid digested in a hot plate as described in Gashu et al.^{46 (link)}. Briefly, about 0.2 g of sample was weighed into digestion tubes and placed into a heating block (Multicube 48, Anton Paar Ltd, UK). Concentrated HNO₃ (8 mL, trace metal grade, Fisher Chemical, USA) was added to each tube and left for 30 min at room temperature. The samples were then heated for 2 h at 115 °C and left to cool before dilution to 50 mL using MilliQ water (18.2 MΩ cm; Fisher Scientific). A further 1 in 10 dilution was undertaken immediately prior to analysis by inductively coupled plasma-mass spectrometry (ICP-MS) (Thermo Fisher Scientific, Bremen, Germany). A certified reference material (CRM, Wheat 1567b, National Institute of Standards and Technology, Gaithersburg, MD, USA) was used to determine % recovery. Operational blanks (n = 20) were analysed at the same time to determine the limit of detection (LOD) for each element.

The oven-dried samples were ground to fine powder, passed through a 2 mm sieve, and then digested with a mixture of nitric acid (HNO₃) and hydrogen peroxide (H₂O₂) (3/1, v/v) in Teflon tanks using an electric heating board at 160℃ thoroughly. The Cd concentration was determined by inductively coupled plasma mass spectrometry (ICP-MS; Thermo Scientific, USA).