Minispec mq 60 benchtop relaxometer

The Gd-SiMPs were characterized using transmission electron microscope (TEM) equipped with energy dispersive spectroscopy (EDS) to provide evidence of the present Gd³⁺-ions on the surface of the Gd-SiMPs. For this, 10 μL of sample solution were dried on a TEM sample holder (Ted Pella, Inc., lacey formvar/carbon, 400 mesh Cu). The amount of coordinated Gd³⁺-ions to the DOTA moieties of the Gd-SiMPs and Gd-SiMs nanoconstructs were assessed via inductively-coupled plasma optical emission spectrometry (ICP-OES) analysis. For this, the sample solution was first digested in 200 μL 99.99 % trace metals basis 1 M NaOH at 24 °C and then in 0.5 – 1 mL of 26% HClO₃ at 130 °C until dryness and reconstituted in 5 mL of 2 % HNO₃. The Gd-SiMPs were characterized with a scanning electron microscope (SEM) JEOL 6500F to assess structural changes before and after the end of the close to physiological condition challenge. For this, 20 μL of the sample solution was dried on the aluminum SEM specimen mount stubs (Electron Microscopy Sciences, PA, USA). The relaxivity properties of the Gd-SiMPs particles were characterized using a Bruker Minispec mq 60 benchtop relaxometer operating at 1.41 T and 37 °C with a 200 μL aqueous solution of sample contained in a 5 mm probe. MRI images were obtained for particles embedded in 1 % agarose gel using 3 T clinical MRI scanner (Philips Ingenia®).