Development and in vitro study of a bi-specific magnetic resonance imaging molecular probe for hepatocellular carcinoma

Figure 2 Physical characterization of ultra-small superparamagnetic iron oxide probes by transmission electron microscopy and magnetic resonance imaging. A-D: Transmission electron microscopy (TEM) images of ultra-small superparamagnetic iron oxide (USPIO) probes of U, UA, UG, and UAG, respectively. E: The core size distribution of USPIO with a mean diameter of 4.88 nm and a standard deviation of 0.16 nm (n = 147), as determined from the TEM images. F: T2-weighted magnetic resonance images of a series of water solutions containing different concentrations of USPIO as indicated by iron concentration (left) and linear regression fitting of the transversal relaxation rate (1/T2) data vs different iron concentrations for extracting the transverse relaxivity r₂ (right). UAG: Anti-AFP–USPIO–anti-GPC3; UA: Anti-AFP–USPIO; UG: Anti-GPC3–USPIO; U: Unlabeled (non-targeted) USPIO.