The epsilon-AlxFe2-xO3 nanomagnets as MRI contrast agents: Factors influencing transverse relaxivity
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11110%2F20%3A10420898" target="_blank" >RIV/00216208:11110/20:10420898 - isvavai.cz</a>
Alternative codes found
RIV/00216208:11320/20:10420898
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=FJ9QhW4U43" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=FJ9QhW4U43</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1016/j.colsurfa.2020.124423" target="_blank" >10.1016/j.colsurfa.2020.124423</a>
Alternative languages
Result language
angličtina
Original language name
The epsilon-AlxFe2-xO3 nanomagnets as MRI contrast agents: Factors influencing transverse relaxivity
Original language description
Most magnetic materials studied as negative contrast agents for magnetic resonance imaging (MRI) enter the superparamagnetic state with decreasing size of their particles, which is distinguished by thermal fluctuations of particle magnetic moment. In the present study, a novel type of contrast agents based on non-superparamagnetic nanoparticles (nanomagnets) of aluminum-doped epsilon polymorph of Fe2O3 is suggested and used as a model system to elucidate the role of magnetic blocking and other factors in the transverse relaxation of water. Specifically, the dependence of the transverse relaxivity r(2) on the magnetic field (0.47-11.75 T), temperature (278 - 348 K), magnetization, surface modification (silica or citrate) and thickness of silica coating (6 - 21 nm) is analyzed for the epsilon-AlxFe2-xO3 nanoparticles with x = 0.23 and the median size of 21 nm. These nanoparticles evinced higher magnetization than the undoped material and were in the blocked state in the temperature range under study. Further, irreversible magnetization processes were revealed by SQUID magnetometry in aqueous suspension of coated clusters of magnetic crystallites that resulted in the field dependence of r(2). The temperature dependence of r(2) was interpreted by the combination of two different regimes - motional averaging and static dephasing regimes. Slow diffusion of water molecules inside the silica shells was suggested to explain only moderate decrease of r(2) with increasing the coating thickness. Moreover, the performance of the contrast agent was demonstrated not only in ultra-high-field MRI at 11.75 T but also by imaging in vivo on a mouse model at 1 T. Finally, preliminary evaluation of cytotoxicity on rat mesenchymal stem cells did not reveal any significant effects. Due to their low toxicity and high relaxivity, epsilon-AlxFe2-xO3 nanoparticles present a promising starting material for further biomedical applications involving MRI, multimodal contrast agents and theranostic carriers.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10302 - Condensed matter physics (including formerly solid state physics, supercond.)
Result continuities
Project
<a href="/en/project/GA19-02584S" target="_blank" >GA19-02584S: Modification of Néel and Brownian relaxation properties of nanoparticles for magnetic imaging methods</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2020
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Colloids and Surfaces A: Physicochemical and Engineering Aspects
ISSN
0927-7757
e-ISSN
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Volume of the periodical
589
Issue of the periodical within the volume
2020
Country of publishing house
NL - THE KINGDOM OF THE NETHERLANDS
Number of pages
11
Pages from-to
124423
UT code for WoS article
000513861400023
EID of the result in the Scopus database
2-s2.0-85077507452