Synthetic antiferromagnetic nanoparticles as potential contrast agents in MRI.
We present the top-down synthesis of a novel type of MRI T2 contrast agent with great control over size and shape using a colloidal lithography technique. The resulting synthetic antiferromagnetic nanoparticles (SAF-NPs) yield improved relaxivities compared to superparamagnetic iron oxide alternatives (SPIONs). For T2 weighted imaging, the outer sphere relaxation theory has shown that the sensitivity of a T2 contrast agent is dependent on the particle size with an optimal size that exceeds the superparamagnetic limit of SPIONs. With the use of the interlayer exchange coupling effect, the SAF-NPs presented here do not suffer from this limit. Adjusting the outer sphere relaxation theory for spherical particles to SAF-NPs, we show both theoretically and experimentally that the SAF-NP size can be optimized to reach the r2 maximum. With measured r2 values up to 355 s(-1) mM(-1), our SAF-NPs show better performance than commercial alternatives and are competitive with the state-of-the-art. This performance is confirmed in an in vitro MRI study on SKOV3 cells.
IMEC , B-3001 Leuven, Belgium.
Ruben
R
Van Roosbroeck
Willem
W
Van Roy
Tim
T
Stakenborg
Jesse
J
Trekker
Antoine
A
D'Hollander
Tom
T
Dresselaers
Uwe
U
Himmelreich
Jeroen
J
Lammertyn
Liesbet
L
Lagae
D045744:Cell Line, Tumor; D003287:Contrast Media / Q000737:chemistry; D006801:Humans; D060328:Magnetic Phenomena; D008279:Magnetic Resonance Imaging / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D011137:Polystyrenes / Q000737:chemistry
D003287:Contrast Media; D011137:Polystyrenes