How morphology influences relaxivity – comparative study of superparamagnetic iron oxide–polymer hybrid nanostructures. (7th July 2015)

• Record Type: Journal Article
• Authors: Ebert, Sandro; Bannwarth, Markus B.; Musyanovych, Anna; Landfester, Katharina; Münnemann, Kerstin
• Is Part Of: Contrast media & molecular imaging. Volume 10:Number 6(2015:Nov./Dec.)
• Page Start: 456
• Page End: 464
• Publication Date: 2015-07-07
• Subjects: SPIO -- iron oxide -- nanocapsules -- nanoparticles -- MRI -- contrast agent; Diagnostic imaging -- Periodicals; Magnetic resonance imaging -- Periodicals; Contrast media (Diagnostic imaging) -- Periodicals; Contrast Media -- Periodicals; Diagnostic Imaging -- Periodicals; Substances de contraste -- Périodiques; Diagnostics moléculaires -- Périodiques; Imagerie médicale; Substance de contraste; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.0754
• DOI: 10.1002/cmmi.1648
• Languages: English
• ISSNs: 1555-4309

Abstract

Abstract : Superparamagnetic iron oxides (SPIOs) are widely used in MRI as T 2 contrast agents, and interest is still growing. Here, the T2 relaxivity of three different SPIO–polymer hybrid morphologies, i.e. homogeneously distributed iron oxide within a polymer matrix, Janus‐like nanoparticles and polymer nanocapsules containing iron oxides, is studied. Making use of calculations based on theory for agglomerated systems, the obtained T 2 values could be predicted for all different morphologies, except for nanocapsules. Nanocapsules, in contrast to full spheres, allow for water exchange between encapsulated water and bulk water, and thus have two contributions to relaxivity. One originates from the capsules acting as a weakly magnetized cluster and the other stems from the individual SPIOs inside the capsule. Therefore, the relaxivities were also computed using an empirical equation found in the literature, which considers water exchange, resulting in a better T 2 forecast for the nanocapsules. The presented study is the first example of a comparison between measured and calculated relaxivities of nanocapsules. Copyright © 2015 John Wiley & Sons, Ltd. Abstract : Relaxivity of nanoparticles and nanocapsules loaded with superparamagnetic iron oxide is calculated and compared to experimental results. In case of semipermeable nanocapsules, the consideration of water exchange leads to an improved matching between experimental and calculated results.