The FeraSpin series offers six superparamagnetic iron oxide contrast agents specifically formulated for pre-clinical magnetic resonance imaging (MRI): FeraSpin XS, FeraSpin S, FeraSpin M, FeraSpin L, FeraSpin XL, and FeraSpin XXL. These are size-selected, narrowly distributed nanoparticulate agents with well-defined particle sizes derived from FeraSpin R. Their identical composition allows for exclusive size-dependent studies and selection of the most suitable contrast agent for the intended application.
FeraSpin XS to XXL are agents of high relaxivity and enhance the contrast in T1- as well as T2- and T2* weighted MRI. The T2-effect increases with increasing particle size whereas the T1-effect increases with decreasing particle size. On accumulation in cells, the T1-effect diminishes and the T2-effect increases.
Upon intravenous injection, all agents of this series circulate in the bloodstream and are taken up by macrophages. They accumulate in the liver and spleen and are degraded within a few days with their iron being transferred into the physiological iron stores.
The macrophage uptake varies in dependence of particle size. Increased uptake by the Kupffer cells (macrophages of the liver) with increasing particle size leads to a rapid accumulation in the liver and spleen and a short blood circulation time. With decreasing particle size, the uptake by the Kupffer cells is reduced leading to a prolonged circulation time and increased uptake by other macrophages.
The FeraSpin Series is an innovative research toolbox that offers solutions for a wide range of imaging applications. It provides the possibility for selection of the MR contrast properties, the pharmacokinetic properties as well as the iron oxide load and, thus, allows a tailoring of the contrast agent to customer needs.
FeraSpin XS to XXL are indicated for use in MRI of small animals, for example, mice.
They can be used in various applications, such as ex vivo cell labeling or in vivo macrophage labeling for inflammation imaging. Principally, all agents of this series can be used to facilitate the visualization of the liver and spleen as well as visualization of the vasculature.
Note: For liver and spleen imaging the use of FeraSpin R is recommended. In applications where a long blood circulation time and a strong T1-effect are favorable, for example in MR angiography, the use of FeraSpin XS is most suited.