Magnetic Nanoparticles for Biomedicine - Intracellular Delivery: Fundamentals and Applications - page 371

iron-oxide nanoparticles have been used to label the cells, enabling subsequent
MRI visualization in vivo, due to the selective shortening of T 2 T2-relaxation time,
leading to a hypointense (dark) signal. MRI, as a noninvasive method, may then be
used not only to evaluate whether the cells have been successfully engrafted, but
also monitor the time course of cell migration and their survival in the targeted
tissue. This information may further help to optimize the transplantation procedure
in terms of the number of required cells, the method or site of cell administration
and the therapeutic time window after injury during which transplantation will be
most effective (Syková and Jendelová 2005 ).
Detailed information about in vivo applications of magnetic particles has been
described in other chapters of this topic.

5 Conclusions

Magnetic nano- and microparticles have been intensively studied for many years.
Magnetically responsive biocompatible materials represent an extremely important
group of stimuli responsive materials with high potential both in research and appli-
cation area. Various areas of biomedicine have already found a substantial benefit
due to the application of magnetic nano- and microparticles, both for in vitro and
in vivo procedures. In fact, many different types of magnetic materials are available,
however, only a small part of them can be used for possible biomedical applica-
tions. Further progress in this area could be expected if cost effective biocompatible
magnetic particles would become available. Safety and biocompatibility studies of
magnetically responsive materials, in particular long-term toxicity studies, have to
be carried out. The potential of magnetic nanomaterials will probably expand when
complex magnetic nanoparticles and drugs containing (nano)systems will be con-
structed, enabling simultaneously their magnetic navigation, MRI detection and
heat production.

Acknowledgements This research was supported by the Ministry of Education of the Czech
Republic (projects OC 157 - Action COST 868 and OC 09052 - Action COST MP0701), by the
Ministry of Industry and Trade of the Czech Republic (Project No. 2A-1TP1/094), and by
the Research Aim of the Institute of Systems Biology and Ecology (AV0Z60870520).

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