Iron → Ferrous oxide

Participants

Reaction Steps

40 nm dextran-coated iron oxide nanoparticles (NP; 115,000 g/mole per iron core) were dissolved in 1× phosphate buffered saline (PBS; 137 mM NaCl, 10 mM Phosphate, 2.7 mM KCl, pH 7.4) at a concentration of 2 mg/mL. Vivotag-750 fluorophore was labeled on the NPs such that each NP has around 2 VT-750 fluorophores. The linker N-succinimidyl iodoacetate (SIA) was dissolved in DMSO at 20 mg/mL. The two solutions were mixed to obtain a 1-to-7 mass ratio between iron oxide NPs and SIA for 2 hr at room temperature with shaking. Size exclusion chromatography (column diameter×height=1 cm×30 cm; media: Sephadex G-50-coarse) was used to separate out the excess SIA and to exchange NPs into borate buffer (50 mM sodium borate, 5 mM EDTA, pH 8.3).

Provenance & Evidence