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Download fileHybrid Polymeric Nanostructures Stabilized by Zirconium and Gadolinium Ions for Use as Magnetic Resonance Imaging Contrast Agents
journal contribution
posted on 2021-04-29, 08:44 authored by Marjorie Yon, Stéphane Gineste, Giacomo Parigi, Barbara Lonetti, Laure Gibot, Daniel R. Talham, Jean-Daniel Marty, Christophe MingotaudNanostructures called hybrid polyion complexes (HPICs) are formed
by adding metal ions to a solution of a double-hydrophilic block copolymer,
leading to the spontaneous formation of highly monodisperse nano-objects.
In this paper, we propose a simple strategy based on a mixture of
metal ions: one chosen to achieve high chemical stability of the nano-objects
and the second included to provide a desired property to the nanostructure.
Using poly(ethylene oxide)-b-poly(acrylic acid) as
the copolymer, the zirconium ion, added as ZrO2+, was selected
to ensure strong interactions with the polymers to reinforce the stability
of the HPIC architecture. The zirconyl ions were combined with lanthanide
ions, which are often used in contrast agents for proton-magnetic
resonance imaging. Mixing the two metal ions with the copolymer led
to nano-objects with an average radius of ca 11–16 nm. Increasing
the zirconyl mole fraction inside the HPICs leads to excellent chemical
stability of the nano-objects. Unexpectedly, when paired with Gd3+, the mixed metal HPIC exhibits greatly enhanced magnetic
relaxivity relatively to the single-ion Gd3+ HPIC, when
the zirconyl mole fraction increases. This behavior was further studied
by nuclear magnetic relaxation dispersion. The resulting nano-objects
are excellent contrast agents with a good biocompatibility. In addition,
there is significant potential for extending the mixed metal HPIC
platform to other areas of study.