Functionalized single-walled carbon nanotubes containing traces of iron as new negative MRI contrast agents for in vivo imaging.
ABSTRACT Single-walled carbon nanotubes (SWCNTs) containing traces of iron oxide were functionalized by noncovalent lipid-PEG or covalent carboxylic acid function to supply new efficient MRI contrast agents for in vitro and in vivo applications. Longitudinal (r(1)) and transversal (r(2)) water proton relaxivities were measured at 300 MHz, showing a stronger T(2) feature as an MRI contrast agent (r(2)/r(1) = 190 for CO(2) H functionalisation). The r(2) relaxivity was demonstrated to be correlated to the presence of iron oxide in the SWNT-carboxylic function COOH, in comparison to iron-free ones. Biodistribution studies on mice after a systemic injection showed a negative MRI contrast in liver, suggesting the presence of the nanotubes in this organ until 48 h after i.v. injection. The presence of carbon nanotubes in liver was confirmed after ex vivo carbon extraction. Finally, cytotoxicity studies showed no apparent effect owing to the presence of the carbon nanotubes. The functionalized carbon nanotubes were well tolerated by the animals at the dose of 10 µg g(-1) body weight.
Full-textDOI: · Available from: Cyrille Richard, Nov 28, 2014
SourceAvailable from: Slawomir Boncel[Show abstract] [Hide abstract]
ABSTRACT: Fe3+ ions were anchored via complexation onto the oxidized multiwall carbon nanotubes containing encapsulated iron-based nanoparticles (Fe@O-MWCNTs) yielding hybrids Fe(III)/Fe@O-MWCNTs for application as MRI contrast agents. After washing, no free Fe3+ ions were observed in the solution. A 120 mg Fe3+ was coordinated by each 1 gram of Fe@O-MWCNTs with a formation of stable hybrids. Relaxation times T1 and T2 of water protons were measured for the suspensions of hybrids. At 7.1 T relaxivity, r2 of Fe@O-MWCNT and Fe(III)/Fe@O-MWCNT was 25 and 35 s(-1) ml mg(-1), respectively, whereas at 0.4 T r2-values were equal. Additionally, T1/T2 ratio was found in a range of 17-104, which is a promising value in the light of application of the proposed materials as potential T2 MRI contrast agents.Materials Letters 12/2014; 136:34–36. DOI:10.1016/j.matlet.2014.07.174 · 2.27 Impact Factor
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ABSTRACT: Carbon nanotubes (CNTs) are one of the most promising nanomaterials to be used in biomedicine for drug/gene delivery as well as biomedical imaging. This study develops radio-labeled, iron oxide-decorated multiwalled CNTs (MWNTs) as dual magnetic resonance (MR) and single photon emission computed tomography (SPECT) contrast agents. Hybrids containing different amounts of iron oxide are synthesized by in situ generation. Physicochemical characterisations reveal the presence of superparamagnetic iron oxide nanoparticles (SPION) granted the magnetic properties of the hybrids. Further comprehensive examinations including high resolution transmission electron microscopy (HRTEM), fast Fourier transform simulations, X-ray diffraction, and X-ray photoelectron spectroscopy assure the conformation of prepared SPION as γ-Fe2O3. High r2 relaxivities are obtained in both phantom and in vivo MRI compared to the clinically approved SPION Endorem. The hybrids are successfully radio labeled with technetium-99m through a functionalized bisphosphonate and enable SPECT/CT imaging and γ-scintigraphy to quantitatively analyze the biodistribution in mice. No abnormality is found by histological examination and the presence of SPION and MWNT are identified by Perls stain and Neutral Red stain, respectively. TEM images of liver and spleen tissues show the co-localization of SPION and MWNTs within the same intracellular vesicles, indicating the in vivo stability of the hybrids after intravenous injection. The results demonstrate the capability of the present SPION–MWNT hybrids as dual MRI and SPECT contrast agents for in vivo use.Advanced Functional Materials 04/2014; 24(13). DOI:10.1002/adfm.201302892 · 10.44 Impact Factor
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ABSTRACT: Multi-modal imaging guided photothermal therapy with single-walled carbon nanotubes affords effective destruction of primary tumors together with cancer cells in sentinel lymph nodes. This results in remarkably prolonged mouse survival compared to mice treated by elimination of only the primary tumor by either surgery or conventional photothermal therapy.Advanced Materials 08/2014; 26(32). DOI:10.1002/adma.201401825 · 15.41 Impact Factor