Covalent functionalization of multi-walled carbon nanotubes with a gadolinium chelate for efficient T1-weighted magnetic resonance imaging

Given the promise of carbon nanotubes (CNTs) for photothermal therapy, drug delivery, tissue engineering, and gene therapy, there is a need for non-invasive imaging methods to monitor CNT distribution and fate in the body. In this study, non-ionizing whole-body high field magnetic resonance imaging (MRI) is used to follow the distribution of water-dispersible non-toxic functionalized CNTs administrated intravenously to mice. Oxidized CNTs are endowed with positive MRI contrast properties by covalent functionalization with the chelating ligand diethylenetriaminepentaacetic dianhydride (DTPA), followed by chelation to Gd. The structural and magnetic properties, MR relaxivities, cellular uptake, and application for MRI cell imaging of Gd-CNTs in comparison to the precursor oxidized CNTs are evaluated. Despite the intrinsic T contrast of oxidized CNTs internalized in macrophages, the anchoring of paramagnetic gadolinium onto the nanotube sidewall allows efficient T contrast and MR signal enhancement, which is preserved after CNT internalization by cells. Hence, due to their high dispersibility, Gd-CNTs have the potential to produce positive contrast in vivo following injection into the bloodstream. The uptake of Gd-CNTs in the liver and spleen is assessed using MRI, while rapid renal clearance of extracellular Gd-CNTs is observed, confirming the evidences of other studies using different imaging modalities

Intercellular carbon nanotube translocation assessed by flow cytometry imaging.

International audienceThe fate of carbon nanotubes in the organism is still controversial. Here, we propose a statistical high-throughput imaging method to localize and quantify functionalized multiwalled carbon nanotubes in cells. We give the first experimental evidence of an intercellular translocation of carbon nanotubes. This stress-induced longitudinal transfer of nanomaterials is mediated by cell-released microvesicles known as vectors for intercellular communication. This finding raises new critical issues for nanotoxicology, since carbon nanotubes could be disseminated by circulating extracellular cell-released vesicles and visiting several cells in the course of their passage into the organism

Covalent functionalization of multi-walled carbon nanotubes with a gadolinium chelate for efficient T1-weighted magnetic resonance imaging

Given the promise of carbon nanotubes (CNTs) for photothermal therapy, drug delivery, tissue engineering, and gene therapy, there is a need for non-invasive imaging methods to monitor CNT distribution and fate in the body. In this study, non-ionizing whole-body high field magnetic resonance imaging (MRI) is used to follow the distribution of water-dispersible non-toxic functionalized CNTs administrated intravenously to mice. Oxidized CNTs are endowed with positive MRI contrast properties by covalent functionalization with the chelating ligand diethylenetriaminepentaacetic dianhydride (DTPA), followed by chelation to Gd. The structural and magnetic properties, MR relaxivities, cellular uptake, and application for MRI cell imaging of Gd-CNTs in comparison to the precursor oxidized CNTs are evaluated. Despite the intrinsic T contrast of oxidized CNTs internalized in macrophages, the anchoring of paramagnetic gadolinium onto the nanotube sidewall allows efficient T contrast and MR signal enhancement, which is preserved after CNT internalization by cells. Hence, due to their high dispersibility, Gd-CNTs have the potential to produce positive contrast in vivo following injection into the bloodstream. The uptake of Gd-CNTs in the liver and spleen is assessed using MRI, while rapid renal clearance of extracellular Gd-CNTs is observed, confirming the evidences of other studies using different imaging modalities