Staff directory

Publications

2017

  • Encapsulation of two-dimensional materials inside carbon nanotubes: Towards an enhanced synthesis of single-layered metal halides

    Sandoval S., Pach E., Ballesteros B., Tobias G. Carbon; 123: 129 - 134. 2017. 10.1016/j.carbon.2017.07.031. IF: 6.337

    The unique properties of two-dimensional (2D) nanomaterials make them highly attractive for a wide range of applications. As a consequence, several top-down and bottom up approaches are being explored to isolate or synthesize single-layers of 2D materials in a reliable manner. Here we report on the synthesis of individual layers of several 2D van der Waals solids, namely CeI3, CeCl3, TbCl3 and ZnI2 by template-assisted growth using carbon nanotubes as directing agents, thus proving the versatility of this approach. Once confined, the metal halides can adopt different structures including single-layered metal halide nanotubes, which formation is greatly enhanced by increasing the temperature of synthesis. This opens up a new strategy for the isolation of individual layers of a wide variety of metal halides, a family of 2D materials that has been barely explored. © 2017 Elsevier Ltd


  • Evaluation of the immunological profile of antibody-functionalized metal-filled single-walled carbon nanocapsules for targeted radiotherapy

    Perez Ruiz De Garibay A., Spinato C., Klippstein R., Bourgognon M., Martincic M., Pach E., Ballesteros B., Ménard-Moyon C., Al-Jamal K.T., Tobias G., Bianco A. Scientific Reports; 7 ( 42605) 2017. 10.1038/srep42605. IF: 4.259

    This study investigates the immune responses induced by metal-filled single-walled carbon nanotubes (SWCNT) under in vitro, ex vivo and in vivo settings. Either empty amino-functionalized CNTs [SWCNT-NH 2 (1)] or samarium chloride-filled amino-functionalized CNTs with [SmCl 3 @SWCNT-mAb (3)] or without [SmCl 3 @SWCNT-NH 2 (2)] Cetuximab functionalization were tested. Conjugates were added to RAW 264.7 or PBMC cells in a range of 1 μg/ml to 100 μg/ml for 24 h. Cell viability and IL-6/TNFα production were determined by flow cytometry and ELISA. Additionally, the effect of SWCNTs on the number of T lymphocytes, B lymphocytes and monocytes within the PBMC subpopulations was evaluated by immunostaining and flow cytometry. The effect on monocyte number in living mice was assessed after tail vein injection (150 μg of each conjugate per mouse) at 1, 7 and 13 days post-injection. Overall, our study showed that all the conjugates had no significant effect on cell viability of RAW 264.7 but conjugates 1 and 3 led to a slight increase in IL-6/TNFα. All the conjugates resulted in significant reduction in monocyte/macrophage cell numbers within PBMCs in a dose-dependent manner. Interestingly, monocyte depletion was not observed in vivo, suggesting their suitability for future testing in the field of targeted radiotherapy in mice. © The Author(s) 2017.


  • Filling Single-Walled Carbon Nanotubes with Lutetium Chloride: A Sustainable Production of Nanocapsules Free of Nonencapsulated Material

    Kierkowicz M., González-Domínguez J.M., Pach E., Sandoval S., Ballesteros B., Da Ros T., Tobias G. ACS Sustainable Chemistry and Engineering; 5 (3): 2501 - 2508. 2017. 10.1021/acssuschemeng.6b02850. IF: 5.951

    Filled carbon nanotubes are of interest for a wide variety of applications ranging from sensors to magnetoelectronic devices and going through the development of smart contrast and therapeutic agents in the biomedical field. In general, regardless of the method employed, bulk filling of carbon nanotubes results in the presence of a large amount of external nonencapsulated material. Therefore, further processing is needed to achieve a sample in which the selected payload is present only in the inner cavities of the nanotubes. Here, we report on a straightforward approach that allows the removal of nonencapsulated compounds in a time efficient and environmentally friendly manner, using water as a "green" solvent, while minimizing the residual waste. The results presented herein pave the way toward the production of large amounts of high-quality closed-ended filled nanotubes, also referred to as carbon nanocapsules, readily utilizable in the foreseen applications. © 2017 American Chemical Society.


  • Inductively coupled remote plasma-enhanced chemical vapor deposition (rPE-CVD) as a versatile route for the deposition of graphene micro- and nanostructures

    Cuxart M.G., Šics I., Goñi A.R., Pach E., Sauthier G., Paradinas M., Foerster M., Aballe L., Fernandez H.M., Carlino V., Pellegrin E. Carbon; 117: 331 - 342. 2017. 10.1016/j.carbon.2017.02.067. IF: 6.337

    Multiple layers of graphene thin films with micro-crystalline orientation and vertical graphene nano-sheets were grown on different substrates (i.e., polycrystalline nickel foil, Ni(111), highly oriented pyrolytic graphite) using a single-step process based on low-pressure remote Plasma-Enhanced Chemical Vapor Deposition (rPE-CVD). In contrast to previous studies, a novel basic approach to this technique including a new remote inductively coupled RF plasma source has been used to (i) minimize the orientational effect of the plasma electrical fields during the catalyst-free growth of graphene nano-sheets, (ii) warrant for a low graphene defect density via low plasma kinetics, (iii) decouple the dissociation process of the gas from the growth process of graphene on the substrate, (iv) tune the feedstock gas chemistry in view of improving the graphene growth, and (v) reduce the growth temperature as compared to conventional chemical vapor deposition (CVD). In order to study the various aspects of the rPE-CVD graphene growth modes and to assess the characteristics of the resulting graphene layers, Raman spectroscopy, XPS, SEM, and STM were used. The results give evidence for the successful performance of this new rPE-CVD plasma deposition source, that can be combined with in situ UHV-based processess for the production of, e. g., hybrid metal ferromagnet/graphene systems. © 2017 Elsevier Ltd


2016

  • Carbon nanotubes allow capture of krypton, barium and lead for multichannel biological X-ray fluorescence imaging

    Serpell C.J., Rutte R.N., Geraki K., Pach E., Martincic M., Kierkowicz M., De Munari S., Wals K., Raj R., Ballesteros B., Tobias G., Anthony D.C., Davis B.G. Nature Communications; 7 ( 13118) 2016. 10.1038/ncomms13118. IF: 11.329

    The desire to study biology in situ has been aided by many imaging techniques. Among these, X-ray fluorescence (XRF) mapping permits observation of elemental distributions in a multichannel manner. However, XRF imaging is underused, in part, because of the difficulty in interpreting maps without an underlying cellular 'blueprint'; this could be supplied using contrast agents. Carbon nanotubes (CNTs) can be filled with a wide range of inorganic materials, and thus can be used as 'contrast agents' if biologically absent elements are encapsulated. Here we show that sealed single-walled CNTs filled with lead, barium and even krypton can be produced, and externally decorated with peptides to provide affinity for sub-cellular targets. The agents are able to highlight specific organelles in multiplexed XRF mapping, and are, in principle, a general and versatile tool for this, and other modes of biological imaging. © 2016 The Author(s).


  • Design of antibody-functionalized carbon nanotubes filled with radioactivable metals towards a targeted anticancer therapy

    Spinato C., Perez Ruiz De Garibay A., Kierkowicz M., Pach E., Martincic M., Klippstein R., Bourgognon M., Wang J.T.-W., Ménard-Moyon C., Al-Jamal K.T., Ballesteros B., Tobias G., Bianco A. Nanoscale; 8 (25): 12626 - 12638. 2016. 10.1039/c5nr07923c. IF: 7.760

    In the present work we have devised the synthesis of a novel promising carbon nanotube carrier for the targeted delivery of radioactivity, through a combination of endohedral and exohedral functionalization. Steam-purified single-walled carbon nanotubes (SWCNTs) have been initially filled with radioactive analogues (i.e. metal halides) and sealed by high temperature treatment, affording closed-ended CNTs with the filling material confined in the inner cavity. The external functionalization of these filled CNTs was then achieved by nitrene cycloaddition and followed by the derivatization with a monoclonal antibody (Cetuximab) targeting the epidermal growth factor receptor (EGFR), overexpressed by several cancer cells. The targeting efficiency of the so-obtained conjugate was evaluated by immunostaining with a secondary antibody and by incubation of the CNTs with EGFR positive cells (U87-EGFR+), followed by flow cytometry, confocal microscopy or elemental analyses. We demonstrated that our filled and functionalized CNTs can internalize more efficiently in EGFR positive cancer cells. © The Royal Society of Chemistry 2016.


  • Gadolinium-functionalised multi-walled carbon nanotubes as a T1 contrast agent for MRI cell labelling and tracking

    Servant A., Jacobs I., Bussy C., Fabbro C., Da Ros T., Pach E., Ballesteros B., Prato M., Nicolay K., Kostarelos K. Carbon; 97: 126 - 133. 2016. 10.1016/j.carbon.2015.08.051. IF: 6.198

    The development of efficient contrast agents for cell labelling coupled with powerful medical imaging techniques is of great interest for monitoring cell trafficking with potential clinical applications such as organ repair and regenerative medicine. In this paper, functionalised multi-walled carbon nanotubes (MWNTs) were engineered for cell labelling in T1-weighted MRI applications. These sophisticated constructs were covalently functionalised with the gadolinium (Gd) chelating agent, diethylene triamine pentaacetic acid (DTPA), enabling tight attachment of Gd atoms onto the nanotube surface. The resulting Gd-labelled MWNTs were found to be stable over 2 weeks in water and mouse serum and high payload of Gd atoms could be loaded onto the nanotubes. The r1 relaxivity of the Gd-MWNTs was a 3-fold higher than of the clinically approved T1 contrast agent Magnevist at a magnetic field strength of 7T. The contrast efficiency, expressed as the r1 relaxivity, of the Gd-MWNTs in Human Umbilical Vein Endothelial cells (HUVEC) was investigated at 7T and was found to be around 6.6 mM-1 s-1. There was no reduction of the contrast efficiency after internalisation in HUVECs, which was imparted to the ability of carbon nanotubes to translocate the cell membrane. © 2015 The Authors. Published by Elsevier Ltd.


  • Synthesis of dry SmCl3from Sm2O3revisited. Implications for the encapsulation of samarium compounds into carbon nanotubes

    Martincic M., Frontera C., Pach E., Ballesteros B., Tobias G. Polyhedron; 116: 116 - 121. 2016. 10.1016/j.poly.2016.03.045. IF: 2.108

    Samarium is a rare-earth metal with several applications in materials science. It is used in organic chemistry as a reducing agent and it is the active payload in samarium-153 lexidronam, a drug being used for palliative treatment of bone metastases. Recently, the encapsulation of samarium compounds into the cavities of carbon nanotubes has attracted interest for the development of the next generation of radiopharmaceuticals. In the present study, we explore different routes to afford the encapsulation of samarium based materials into single-walled carbon nanotubes. Anhydrous samarium(III) chloride, despite being highly hygroscopic, raises as an excellent candidate to achieve a high filling efficiency. We provide a protocol that allows the synthesis of anhydrous samarium(III) chloride starting from samarium(III) oxide in a fast and simple manner. Synchrotron X-ray powder diffraction confirmed the crystallinity and purity of the synthesized SmCl3. © 2016 Elsevier Ltd


2015

  • Quantitative monitoring of the removal of non-encapsulated material external to filled carbon nanotube samples

    Martincic M., Pach E., Ballesteros B., Tobias G. Physical Chemistry Chemical Physics; 17 (47): 31662 - 31669. 2015. 10.1039/c5cp04664e. IF: 4.493

    The endohedral functionalization of carbon nanotubes with both organic and inorganic materials allows the development of tailored functional hybrids whose properties benefit from the synergistic effects of the constituent compounds. Bulk filling of carbon nanotubes (CNTs) results in samples that contain a large amount of non-encapsulated material external to the CNTs. The presence of the external material is detrimental to the processing and application of the resulting hybrids. Here we introduce the use of UV-Vis spectroscopy to monitor the cleaning process, i.e. the elimination of non-encapsulated compounds. Chrome azurol S has been employed to assess the bulk removal of external samarium(iii) chloride from filled single-walled carbon nanotubes. Chrome azurol S is of interest since it can be used to quantify a large variety of materials in a fast, accurate and reliable manner. The parameters that control the cleaning process have been optimized, including the time, temperature, volume and sonication, to achieve a fast and complete removal of the external material. © 2015 the Owner Societies.


  • The interaction of carbon nanotubes with an invitro blood-brain barrier model and mouse brain invivo

    Kafa H., Wang J.T.W., Rubio N., Venner K., Anderson G., Pach E., Ballesteros B., Preston J.E., Abbott N.J., Al-Jamal K.T. Biomaterials; 53: 437 - 452. 2015. 10.1016/j.biomaterials.2015.02.083. IF: 8.557

    Carbon nanotubes (CNTs) are a novel nanocarriers with interesting physical and chemical properties. Here we investigate the ability of amino-functionalized multi-walled carbon nanotubes (MWNTs-NH3+) to cross the Blood-Brain Barrier (BBB) invitro using a co-culture BBB model comprising primary porcine brain endothelial cells (PBEC) and primary rat astrocytes, and invivo following a systemic administration of radiolabelled f-MWNTs. Transmission Electron microscopy (TEM) confirmed that MWNTs-NH3+ crossed the PBEC monolayer via energy-dependent transcytosis. MWNTs-NH3+ were observed within endocytic vesicles and multi-vesicular bodies after 4 and 24h. A complete crossing of the invitro BBB model was observed after 48h, which was further confirmed by the presence of MWNTs-NH3+ within the astrocytes. MWNT-NH3+ that crossed the PBEC layer was quantitatively assessed using radioactive tracers. A maximum transport of 13.0±1.1% after 72h was achieved using the co-culture model. f-MWNT exhibited significant brain uptake (1.1±0.3% injected dose/g) at 5min after intravenous injection in mice, after whole body perfusion with heparinized saline. Capillary depletion confirmed presence of f-MWNT in both brain capillaries and parenchyma fractions. These results could pave the way for use of CNTs as nanocarriers for delivery of drugs and biologics to the brain, after systemic administration. © 2015 The Authors.


2014

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

    Marangon, I.; Ménard-Moyon, C.; Kolosnjaj-Tabi, J.; Béoutis, M.L.; Lartigue, L.; Alloyeau, D.; Pach, E.; Ballesteros, B.; Autret, G.; Ninjbadgar, T.; Brougham, D.F.; Bianco, A.; Gazeau, F. Advanced Functional Materials; 24 (45): 7173 - 7186. 2014. 10.1002/adfm.201402234. IF: 10.439


  • Production of water-soluble few-layer graphene mesosheets by dry milling with hydrophobic drug

    Rubio, N.; Serra-Maia, R.; Kafa, H.; Mei, K.-C.; Al-Jamal, K.T.; Luckhurst, W.; Zloh, M.; Festy, F.; Richardson, J.P.; Naglik, J.R.; Pach, E.; Ballesteros, B. Langmuir : the ACS journal of surfaces and colloids; 30 (49): 14999 - 15008. 2014. 10.1021/la5038475. IF: 4.384