Relaxivity Enhancement of Ditopic Bishydrated Gadolinium(III) Complexes Conjugated to Mesoporous Silica Nanoparticles. Issue 20 (6th April 2018)

• Record Type: Journal Article
• Authors: Carniato, Fabio; Tei, Lorenzo; Martinelli, Jonathan; Botta, Mauro
• Is Part Of: European journal of inorganic chemistry. Issue 20/21(2018)
• Page Start: 2363
• Page End: 2368
• Publication Date: 2018-04-06
• Subjects: Lanthanides -- Chelates -- Mesoporous silica -- Relaxivity -- Imaging agents -- Nanoparticles; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201800041
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : Dinuclear Gd 3+ complexes containing thermodynamically stable and bishydrated GdAAZTA (AAZTA = 6‐amino‐6‐methylperhydro‐1, 4‐diazepinetetraacetic acid) chelates were covalently linked to the surfaces of mesoporous silica nanoparticles and decorated with poly(ethylene glycol) (PEG5000 ) molecules. The surface and textural properties of the samples were analyzed. A detailed 1 H NMR relaxometric characterization as a function of the applied magnetic‐field strength was performed for the conjugated systems in aqueous solutions to evaluate their efficacy as potential magnetic resonance imaging (MRI) diagnostic probes. The samples showed enhanced longitudinal relaxivity values (37.5 mm –1 s –1 per ion at 0.7 T and 310 K) compared with those of the free complex (+270 %) and related nanosystems based on monohydrated Gd 3+ chelates (+42 %). The relaxivity gain is the result of the rational design of the ditopic complex, as it ensures an increased hydration state ( q = 2), improvement of the rotational dynamics and a fast rate of water exchange between the inner coordination sphere and the bulk. These favourable properties are obtained without compromise to the high thermodynamic stability and kinetic inertness of the chelating units. Abstract : Dinuclear bishydrated Gd 3+ chelates are linked to the surfaces of mesoporous silica nanoparticles and then PEGylated. The nanoprobes show improved longitudinal relaxivity values compared with those of the free ditopic complex and systems functionalized with monoaqua Gd 3+ chelates.