Figure 1a:

Nanomaterial synthesis. Ultrasmall superparamagnetic iron oxide (USPIO) clusters were mixed with silver (Ag), which acts as a catalyst allowing gold (Au) to coat USPIO clusters. Polyethylene glycol (PEG) is added, which contains sulfyl (SH) and hydroxyl (COOH) groups at opposite ends of the molecules. The sulfonyl group binds to the gold shell, while the hydroxyl group binds to a commercially available coupling agent (1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysulfosuccinimide, or EDC-NHS). The anti-MG1 mAb can then be coupled to the nanoparticle. (a) Illustration shows synthesis of mAb conjugated HNP, (b–d) transmission electron microscopic images show USPIO clusters measuring (b) 200 nm, (c) 200 nm, and (d) 100 nm. Graphs show size distribution measured with (e) Zetasizer and (f) absorption band of USPIO clusters and HNP.