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Journal articles
Long-term live cells observation of internalized fluorescent Fe@C nanoparticles in constant magnetic field
Abstract : Background: Theranostics application of superparamagnetic nanoparticles based on magnetite and maghemite is
impeded by their toxicity. The use of additional protective shells significantly reduced the magnetic properties of the
nanoparticles. Therefore, iron carbides and pure iron nanoparticles coated with multiple layers of onion-like carbon
sheath seem to be optimal for biomedicine. Fluorescent markers associated with magnetic nanoparticles provide reliable
means for their multimodal visualization. Here, biocompatibility of iron nanoparticles coated with graphite-like
shell and labeled with Alexa 647 fluorescent marker has been investigated.
Methods: Iron core nanoparticles with intact carbon shells were purified by magnetoseparation after hydrochloric
acid treatment. The structure of the NPs (nanoparticles) was examined with a high resolution electron microscopy.
The surface of the NPs was alkylcarboxylated and further aminated for covalent linking with Alexa Fluor 647 fluorochrome
to produce modified fluorescent magnetic nanoparticles (MFMNPs). Live fluorescent imaging and correlative
light-electron microscopy were used to study the NPs intracellular distribution and the effects of constant magnetic
field on internalized NPs in the cell culture were analyzed. Cell viability was assayed by measuring a proliferative pool
with Click-IT labeling.
Results: The microstructure and magnetic properties of superparamagnetic Fe@C core–shell NPs as well as their
endocytosis by living tumor cells, and behavior inside the cells in constant magnetic field (150 mT) were studied.
Correlative light-electron microscopy demonstrated that NPs retained their microstructure after internalization by
the living cells. Application of constant magnetic field caused orientation of internalized NPs along power lines thus
demonstrating their magnetocontrollability. Carbon onion-like shells make these NPs biocompatible and enable
long-term observation with confocal microscope. It was found that iron core of NPs shows no toxic effect on the cell
physiology, does not inhibit the cell proliferation and also does not induce apoptosis.
Conclusions: Non-toxic, biologically compatible superparamagnetic fluorescent MFMNPs can be further used for
biological application such as delivery of biologically active compounds both inside the cell and inside the whole
organism, magnetic separation, and magnetic resonance imaging (MRI) diagnostics.
https://hal-univ-tours.archives-ouvertes.fr/hal-02525639
Contributor : Catherine Chenu <>
Submitted on : Tuesday, March 31, 2020 - 9:01:40 AM
Last modification on : Tuesday, July 14, 2020 - 11:04:09 AM
Contributor : Catherine Chenu <>
Submitted on : Tuesday, March 31, 2020 - 9:01:40 AM
Last modification on : Tuesday, July 14, 2020 - 11:04:09 AM
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