Sncl2

The following chemicals were used as received from commercial sources, including SnI₂ (99.99%, Sigma-Aldrich), CsI (99.9%, Sigma-Aldrich), CH(NH₂)₂I (FAI) (>98%, Tokyo Chemical Industry Co., Japan), SnF₂ (>99%, Sigma-Aldrich), SnCl₂(>99%, Sigma-Aldrich), PCBM (99.5% Lumtec Co., Taiwan), bathocuproine (>99%, Wako), ethylenediammonium diiodide (EDAI₂) (>98%, Tokyo Chemical Industry Co., Japan). All solutions were filtered with 0.2 μm PTFE filter before use.

Acetonitrile and methanol of HPLC grade were purchased from Merck (Darmstadt, Germany). Hydrofluoric acid (48% in water), SnCl₂, and KAl(SO₄)₂ × 12 H₂O were purchased from Sigma-Aldrich (Steinheim, Germany). All aqueous solutions were prepared using deionized Milli Q water. Weld (Reseda luteola L.), Persian berries (Rhamnimaturi), and Brazilwood (Caesalpinia Sappan Linn) were obtained from Kremer Pigmente (Aichstetten, Germany) in dried form. Ethylene-norbornene random copolymer, with the commercial name Topas Elastomer E140 (EN), was provided by TOPAS Advanced Polymers (Raunheim, Germany).

Technetium-99m was obtained by elution using a ⁹⁹Mo/^99mTc generator. HYNIC-FGF-2 (50 µL, 2 mg/mL) was labelled with different amounts of freshly eluted ^99mTcO4 (NaCl 0.9%). The reaction was conducted in the presence of different amounts of co-ligand Tricine (1, 10 or 20 mg in 50 µL) and with constant amount of stannous chloride (SnCl₂) (10 µg in 1 µL) to evaluate the best labeling conditions [20 (link)]. Tricine (Sigma-Aldrich, St. Louis, MO, USA) was dissolved in distilled water and SnCl₂ (Sigma-Aldrich, St. Louis, MO, USA) in purged HCl 0.1 M (mg/mL). The reaction solution was incubated for 10 min at room temperature and the labeling efficiency (LE%) and colloid percentages were evaluated using instant Thin Layer Chromatography (iTLC) and high-performance liquid chromatography (HPLC). To purify the ^99mTc-HYNIC-FGF-2 from the free ^99mTc, a PD-10 desalting column containing Sephadex G-25 resin (GE Healthcare, Uppsala, Sweden) was used.

Graphite oxide was synthesized from graphite powder by a modified Hummers’ method. The prepared graphite oxide (20 mg) was exfoliated in distilled water (10 mL) by sonication for 60 min to form a homogeneous suspension. To prepare ITO/RGO, SnCl₂·2H₂O (400 mg, Sigma-Aldrich, 98%) and InCl₃ (44 mg, Sigma-Aldrich, 98%) were dissolved in 200 ml HCl solution (0.02 M, Sigma-Aldrich, 37%). The graphite oxide suspension and SnCl₂–HCl solution were mixed under vigorous stirring while adding 500 mg urea (Sigma-Aldrich, 98%) to form a uniform solution. The resulting solution was ultrasonicated for 30 min, then refluxed at 120 °C for 6 h. When cooled to room temperature, the solid products were washed with distilled water 6 times to remove the byproducts, followed by drying at 100 °C under vacuum overnight. The powders were further heat-treated in a tube furnace at 500 °C for 2 h under Ar flow with a heating rate of 2 °C min⁻¹. SnO₂/RGO and In₂O₃/RGO were prepared in the same way without the presence of indium and tin additions, respectively.

The labeling process was done using 150 μL of the bevacizumab incubated with stannous chloride (SnCl₂) solutions (80 μL/mL) (Sigma-Aldrich) for 20 minutes at room temperature. Then this solution was incubated with 100 μCi (approximately 300 μL) of technetium-99m for another 10 minutes in order to label bevacizumab with 99mTc [19 (link), 20 (link)].