Iron oxide, superparamagnetic

Because the appearance of the superparamagnetic effect depends on the particle size and on the anisotropy constant, it is often displayed at room temperature by iron oxides <10 nm in size, for example, soil iron oxides. Superparamagnetic relaxation may be counteracted by lowering the temperature and thereby increasing x. Superparamagnetic particles will usually be ordered below a blocking temperature,Tb, which is ... 

Muller, K., Skepper, J.N., Posfai, M., Trivedi, R., Howarth, S., Corot, C., Lancelot, E., Thompson, P.W., Brown, A.P., and Gillard, J.H. (2007) Effect of ultrasmall superparamagnetic iron oxide nanoparticles (Ferumoxtran-10) on human monocyte-macrophages invitro. Biomaterials, 28 (9), 1629-1642. 

The chemical composition of particles can be just as varied as their shape. Commercial particles can consist of polymers or copolymers, inorganic constructs, metals and semiconductors, superparamagnetic composites, biodegradable constructs, and synthetic dendrimers and dendrons. Often, both the composition of a particle and its shape govern its suitability for a particular purpose. For instance, composite particles containing superparamagnetic iron oxide typically are used for small-scale affinity separations, especially for cell separations followed by flow cytometry analysis or fluorescence-activated cell sorting (FACS). Core-shell semiconductor particles, by... 

Figure 1. MSC accumulate within the scar area. MSC fed with superparamagnetic iron oxide nanoparticles and injected into the border zone of infarcted myocardinm migrate into the infracted area.

Ittrich, H., Lange, C., Dahnke, H., Zander, A.R., Adam, G. and Nolte-Ernsting, C. (2005) Labeling of mesenchymal stem cells with different superparamagnetic particles of iron oxide and detectability with MRI at 3T. Rofo 177, 1151-63. 

U)SPIO (ultrasmall) superparamagnetic iron oxide (h)TfR (human) transferrin receptor... 

Many cells, such as lymphocytes, do however lack efficient internalizing receptor systems. The development of a new and effective internalizing pathway thus appears as a very important goal. Weissleder et al. [83, 96] have tried to develop such a system by attaching a superparamagnetic iron oxide to a membrane translocating signal (MTS) peptide. Several MTSs have been described... 

Scheme 7. Preparation of tat-peptide labeled superparamagnetic iron oxide particles (In-DTPA-fluo-tat-S-S-CLIO) according to Weissleder et al. [96]...

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