Details
| Original language | English |
|---|---|
| Pages (from-to) | 2422-2427 |
| Number of pages | 6 |
| Journal | Nano letters |
| Volume | 7 |
| Issue number | 8 |
| Publication status | Published - 20 Jul 2007 |
| Externally published | Yes |
Abstract
Superparamagnetic MnFe2O4 nanocrystals of different sizes were synthesized in high-boiling ether solvent and transferred into water using three different approaches. First, we applied a ligand exchange in order to form a water soluble polymer shell. Second, the particles were embedded into an amphiphilic polymer shell. Third, the nanoparticles were embedded into large micelles formed by lipids. Although all approaches lead to effective negative contrast enhancement, we observed significant differences concerning the magnitude of this effect. The transverse relaxivity, in particular r 2* is greatly higher for the micellar system compared to the polymer-coated particles using same-sized nanoparticles. We also observed an increase in transverse relaxivities with increasing particle size for the polymer-coated nanocrystals. The results are qualitatively compared with theoretical models describing the dependence of relaxivity on the size of magnetic spheres.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Bioengineering
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
- Engineering(all)
- Mechanical Engineering
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In: Nano letters, Vol. 7, No. 8, 20.07.2007, p. 2422-2427.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Size and Surface Effects on the MRI Relaxivity of Manganese Ferrite Nanoparticle Contrast Agents
AU - Tromsdorf, Ulrich I.
AU - Bigall, Nadja C.
AU - Kaul, Michael G.
AU - Bruns, Oliver T.
AU - Nikolic, Marija S.
AU - Mollwitz, Birgit
AU - Sperling, Ralph A.
AU - Reimer, Rudolph
AU - Hohenberg, Heinz
AU - Parak, Wolfgang J.
AU - Förster, Stephan
AU - Beisiegel, Ulrike
AU - Adam, Gerhard
AU - Weller, Horst
PY - 2007/7/20
Y1 - 2007/7/20
N2 - Superparamagnetic MnFe2O4 nanocrystals of different sizes were synthesized in high-boiling ether solvent and transferred into water using three different approaches. First, we applied a ligand exchange in order to form a water soluble polymer shell. Second, the particles were embedded into an amphiphilic polymer shell. Third, the nanoparticles were embedded into large micelles formed by lipids. Although all approaches lead to effective negative contrast enhancement, we observed significant differences concerning the magnitude of this effect. The transverse relaxivity, in particular r 2* is greatly higher for the micellar system compared to the polymer-coated particles using same-sized nanoparticles. We also observed an increase in transverse relaxivities with increasing particle size for the polymer-coated nanocrystals. The results are qualitatively compared with theoretical models describing the dependence of relaxivity on the size of magnetic spheres.
AB - Superparamagnetic MnFe2O4 nanocrystals of different sizes were synthesized in high-boiling ether solvent and transferred into water using three different approaches. First, we applied a ligand exchange in order to form a water soluble polymer shell. Second, the particles were embedded into an amphiphilic polymer shell. Third, the nanoparticles were embedded into large micelles formed by lipids. Although all approaches lead to effective negative contrast enhancement, we observed significant differences concerning the magnitude of this effect. The transverse relaxivity, in particular r 2* is greatly higher for the micellar system compared to the polymer-coated particles using same-sized nanoparticles. We also observed an increase in transverse relaxivities with increasing particle size for the polymer-coated nanocrystals. The results are qualitatively compared with theoretical models describing the dependence of relaxivity on the size of magnetic spheres.
UR - http://www.scopus.com/inward/record.url?scp=34548171034&partnerID=8YFLogxK
U2 - 10.1021/nl071099b
DO - 10.1021/nl071099b
M3 - Article
C2 - 17658761
AN - SCOPUS:34548171034
VL - 7
SP - 2422
EP - 2427
JO - Nano letters
JF - Nano letters
SN - 1530-6984
IS - 8
ER -