Table 1.

Characterization of SPIO used in the study (average of 3 measurements). Nanoparticle concentration was either measured with NanoSight (large SPIO NW) or calculated theoretically, as described. [28] PDI, polydispersity index. All particle solutions were at 1 mg Fe/mL and had less than 0.2 EU/mL endotoxin as measured with Limulus amebocyte lysate assay.

Particle name	Composition	Size (intensity weighted), nm	PDI	Zeta potential, mV
Large SPIO NW	20kDa native dextran, multiple crystals per particle	106 (Z-average), 126 ± 54.42 (peak)	0.16	−7.4 ± 6.8
Small SPIO NW	20kDa native dextran, multiple crystals per particle	67 (Z-average), 81.36 ± 40.35 (peak)	0.22	−6.8 ± 8.8
Ferumoxytol (Feraheme ®)	10kDa reduced carboxymethyl dextran, 1 crystal per particle	26 (Z-average), 26.86 ± 10.53 (peak)	0.27	−15.6 ± 7.4
Ultrasmall SPIO (USPIO)	10kDa reduced T-10 dextran SPIO, 1 crystal per particle	26 (Z-average), 25.96 ± 7.64 (peak)	0.23	−5.0 ± 10.0
Ferumoxtran-10	10kDa native T-10 dextran SPIO, 1-3 crystals per particle	44 (Z-average), 51.19 ± 20.75 (peak)	0.14	−7.2 ± 9.5