PINHO, Sonia L. C.; FANECA, Henrique; GERALDES, Carlos F. G. C.; DELVILLE, Marie-Hélène; CARLOS, Luís D.; ROCHA, João

doi:10.1016/j.biomaterials.2011.09.086

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PINHO, Sonia L. C.
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
Department of Chemistry [CICECO]
Departments of Physics [CICECO]

FANECA, Henrique
Department of Life Sciences

GERALDES, Carlos F. G. C.
Department of Life Sciences

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Article de revue

Ce document a été publié dans

Biomaterials. 2012, vol. 33, n° 3, p. 925-935

Elsevier

Résumé en anglais

The design and synthesis of a combined MRI-optical probe for bio-imaging are reported. The materials studied join the properties of lanthanide (Ln(3+)) complexes and nanoparticles (NPs), offering an excellent solution for bimodal imaging. The hybrid SiO(2)@APS/DTPA:Gd:Ln (Ln = Eu(3+) or Tb(3+)) (APS: 3-aminopropyltriethoxysilane, DTPA: diethylenetriamine pentaacetic acid) system increases the payload of the active magnetic centre (Gd(3+)) and introduces a Ln(3+) long-life excited state (Eu(3+): 0.35 ± 0.02 ms, Tb(3+): 1.87 ± 0.02 ms), with resistance to photobleaching and sharp emission bands. The Eu(3+) ions reside in a single low-symmetry site. Although the photoluminescence emission is not influenced by the simultaneous presence of Gd(3+) and Eu(3+), a moderate r(1) increase and a larger enhancement of r(2) are observed, particularly at high fields, due to susceptibility effects on r(2). The presence of Tb(3+) instead of Eu(3+) further raises r(1) but decreases r(2). These values are constant over a wide (5-13) pH range, indicating the paramagnetic NPs stability and absence of leaching. The uptake of NPs by living cells is fast and results in an intensity increase in the T(1)-weighted MRI images. The optical properties of the NPs in cellular pellets are also studied, confirming their potential as bimodal imaging agents.< Réduire

Mots clés en italien

Nanoparticle

Bimodal imaging

MRI contrast agents

Optical contrast agents

Photoluminescence

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Lanthanide-DTPA grafted silica nanoparticles as bimodal-imaging contrast agents.

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Mots clés en italien

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