Lanthanide-DTPA grafted silica nanoparticles as bimodal-imaging contrast agents
authors Pinho, SLC; Faneca, H; Geraldes, CFGC; Delville, MH; Carlos, LD; Rocha, J
nationality International
journal BIOMATERIALS
author keywords Nanoparticle; Bimodal imaging; MRI contrast agents; Optical contrast agents; Photoluminescence
keywords ORGANIC-INORGANIC HYBRIDS; SOL-GEL APPROACH; DIETHYLENETRIAMINEPENTAACETIC ACID; GAMMA-AMINOPROPYLTRIETHOXYSILANE; EUROPIUM COMPLEXES; LUMINESCENT PROBES; MODIFIED SBA-15; QUANTUM DOTS; MRI; FLUORESCENT
abstract 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. (C) 2011 Elsevier Ltd. All rights reserved.
publisher ELSEVIER SCI LTD
issn 0142-9612
year published 2012
volume 33
issue 3
beginning page 925
ending page 935
digital object identifier (doi) 10.1016/j.biomaterials.2011.09.086
web of science category Engineering, Biomedical; Materials Science, Biomaterials
subject category Engineering; Materials Science
unique article identifier WOS:000298212400021
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