A Top‐Down Synthesis Route to Ultrasmall Multifunctional Gd‐Based Silica Nanoparticles for Theranostic Applications. Issue 19 (19th March 2013)

• Record Type: Journal Article
• Authors: Mignot, Anna; Truillet, Charles; Lux, François; Sancey, Lucie; Louis, Cédric; Denat, Franck; Boschetti, Frédéric; Bocher, Laura; Gloter, Alexandre; Stéphan, Odile; Antoine, Rodolphe; Dugourd, Philippe; Luneau, Dominique; Novitchi, Ghenadie; Figueiredo, Leandro Carlos; de Morais, Paulo Cesar; Bonneviot, Laurent; Albela, Belen; Ribot, François; Van Lokeren, Luk; Déchamps‐Olivier, Isabelle; Chuburu, Françoise; Lemercier, Gilles; Villiers, Christian; Marche, Patrice N.; Le Duc, Géraldine; Roux, Stéphane; Tillement, Olivier; Perriat, Pascal
• Is Part Of: Chemistry. Volume 19:Issue 19(2013)
• Page Start: 6122
• Page End: 6136
• Publication Date: 2013-03-19
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201203003
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>New, ultrasmall nanoparticles with sizes below 5 nm have been obtained. These small rigid platforms (SRP) are composed of a polysiloxane matrix with DOTAGA (1, 4, 7, 10‐tetraazacyclododecane‐1‐glutaric anhydride‐4, 7, 10‐triacetic acid)–Gd<sup>3+</sup> chelates on their surface. They have been synthesised by an original top‐down process: 1) formation of a gadolinium oxide Gd<sub>2</sub>O<sub>3</sub> core, 2) encapsulation in a polysiloxane shell grafted with DOTAGA ligands, 3) dissolution of the gadolinium oxide core due to chelation of Gd<sup>3+</sup> by DOTAGA ligands and 4) polysiloxane fragmentation. These nanoparticles have been fully characterised using photon correlation spectroscopy (PCS), transmission electron microscopy (TEM), a superconducting quantum interference device (SQUID) and electron paramagnetic resonance (EPR) to demonstrate the dissolution of the oxide core and by inductively coupled plasma mass spectrometry (ICP‐MS), mass spectrometry, fluorescence spectroscopy, <sup>29</sup>Si solid‐state NMR, <sup>1</sup>H NMR and diffusion ordered spectroscopy (DOSY) to determine the nanoparticle composition. Relaxivity measurements gave a longitudinal relaxivity <italic>r</italic><sub>1</sub> of 11.9 s<sup>−1</sup> m<sc>M</sc><sup>−1</sup> per Gd at 60 MHz. Finally, potentiometric titrations showed that Gd<sup>3+</sup> is strongly chelated to DOTAGA (complexation constant log<italic>β</italic><sub>110</sub>=24.78) and cellular tests confirmed the that nanoconstructs had a very low toxicity. Moreover, SRPs are excreted from the body by renal clearance. Their efficiency as contrast agents for MRI has been proved and they are promising candidates as sensitising agents for image‐guided radiotherapy.</p> </abstract>