Bioengineering of carbon nanomaterials
Design and applications of filled carbon nanotubes
One of our main research interests is directed towards exploring the applications that the encapsulation of materials inside carbon nanotubes (“carbon nanocapsules”) might have in different areas. Of special interest is their use in the biomedical field, specially in the areas of cancer diagnosis and therapy. Using this approach we have shown that radionuclide filled carbon nanotubes allow ultrasensitive imaging and a complete redirected biodistribution of the encapsulated radionuclides. Surface functionalisation of these nanocapsules offers versatility towards modulation of the in vivo fate of the radioemitting crystals in a manner determined by the nanocapsule that delivers them (Nature Materials 2010. 9, 485; see also “News and Views”: Nature Materials 2010, 9, 467; Nature Chemisty 2010, 604, 2; Nano Today 2010, 5, 245). In the framework of the european network RADDEL, that we are coordinating, we have recently proven the targeting of cancer cells. In this study, the nanocapsules contained in their interior biomedically relevant payloads and their surfaces were covalently modified with antibodies (Nanoscale 2016).
These filled carbon nanotubes also offer great potential as drug delivery systems. In this case a controlled release of the encapsulated payload is desired. To this end we have developed pH-sensitive “nano-corks” that allow a triggered release of the encapsulated compounds by lowering the pH of the aqueous media (Carbon 2010, 48, 1912; Chem. Commun. 2008, 2164). We have recently reviewed the advances on the use of filled carbon nanotubes for biomedical imaging and drug delivery (Expert Opinion on Drug Delivery 2015, 12, 563). In terms of drug delivery we have also recently expanded the work to metal-organic frameworks (MOFs) and reported on light triggered drug delivery (Adv. Func. Mater. 2016).
Chemistry of carbon nanomaterials
Research under the broad heading of “Chemistry of carbon nanomaterials” focuses on different aspects that are essential for the processing and application of these nanomaterials (mainly carbon nanotubes and graphene), ranging from their purification (Carbon 2016, 93, 1059) to the formation of composite materials, going through their functionalisation with both organic and inorganic compounds (Chem. Eur. J. 2015, 21, 16792). The group is also interested in the chemistry and applications of graphene and related materials. In this respect, we have recently demonstrated an enhanced thermal oxidation stability effect for reduced graphene oxide throuhg nitrogen doping (Chem. Eur. J. 2014, 20, 11999-12003). By doping of the graphene structure, it is possible to tailor the electronic and magnetic properties of the material by modulating the band structure to further expand the range of applications (Carbon 2016, 96, 594). We have also recently explored the functionalization of the surface of graphene oxdide with biomedical relevant moieties for cancer therapy (Chem. Eur. J. 2016).
The group is also interested in product manufacturing using scalable methodologies that can be implemented at the industrial level. We have for instance developed protocols for the large scale purification and processing of as-produced carbon nanotube materials in close collaboration with carbon nanotube industrial suppliers. On the other hand we are also working together with the Technological center EURECAT on the scaling-up production of composite materials, with the aim to transfer the technology developed within the group to customer applications.
Manufacturing of inorganic materials
Another area of major interest in our group is the formation of inorganic nanostructures, which can take the form of nanocomposites, nanoparticles, nanotubes or nanorods. Several synthetic approaches are employed for the preparation of these nanoparticulate systems including hydrothermal synthesis and template assisted growth. Initial work focused on the production of silica composites with carbon nanotubes (J. Mater. Chem. 2008, 18, 5344) which then expanded to other kinds of materials. We are for instance currently developing titania nanoparticles that organize in a superstructural nanonecklace. These highly porous systems are of interest for their photocatalytic activity. We also prepare superparamagnetic iron oxide nanoparticles (SPION). These systems have been recently studied for their potential as theragnostic agents in the biomedical field (Adv. Funct. Mater. 2014, 1880-1894, Small 2016). The use of SPION allows both, their detection by magnetic resonance imaging (MRI) and can also be used for therapeutic purposes in hyperthermia.
Core-shell inorganic nanostructures
One of the defining structural features of nanotubular structures is their long inner hollow cavity. Recently, we have demonstrated a new synthetic strategy that allows the formation of core–shell nanotubular structures by using multiwall tungsten sulfide nanotubes as host templates.The relatively large diameter of the tungsten sulfide nanotube (inner and outer diameters of about 10 and 20 nm, respectively) allows conformal folding of the guest layered material on the interior wall of the nanotube template, leading to core–shell inorganic nanotubular structures. In our first example we growth tubular lead iodide structures in the interior of the tungsten sulfide nanotubes (Angew. Chem. Int. Ed. 2009, 48, 1230). More recently we have shown that these novel templating systems can indeed accomodate a wide variety of materials in their interior (Nano Res. 2010, 3, 170). In a recently published paper (Adv. Mater. 2014, 26, 2016-2021) we reported the template assisted growth of single-layered inorganic nanotubes. Single-crystalline lead iodide single-layered nanotubes have been prepared using the inner cavities of carbon nanotubes as hosting templates. The diameter of the resulting inorganic nanotubes is merely dependent on the diameter of the host. This facile method is highly versatile opening up new horizons in the preparation of single-layered nanostructures.
The group is actively participating in several research projects both at national and international level. Some of the recent projects include:
Nanocapsules for Targeted Delivery of Radioactivity, RADDEL (2012-2016).
Network Coordinatior: Dr. Gerard Tobias. RADDEL is an Initial Training Network (ITN), funded by the European Commission FP7. RADDEL is formed by 11 partners and provides an intersectorial platform for the training of young researchers. See: http://projects.icmab.es/raddel/
Development of ultra-sensitive nanotherapeutic anticancer agents for boron neutron capture therapy, NANOTER (2016-2018).
Coordinatior: Dr. Gerard Tobias. Marie-Curie Fellowship (Dr. Gil Gonçalves). Funded by the European Commission H2020.
Graphene reinforce composites for 3D printing technology, 3D-PRINTGRAPh (2016-2018).
Coordinatior: Dr. Gerard Tobias. Marie-Curie Fellowship (Dr. Maria Soria). Funded by the European Commission H2020.
Challenges in inorganic materials for energy applications, CHALENG (2015-2017).
Funded by the Spanish Ministry of Economy and Competitivity. CHALENG aims to developed novel inorganic nanomaterials for energy applications. The work of Dr. Tobias will mainly focus on the design and production of inorganic nanoparticles of a wide variety of materials.
Scale-up production of composite materials, (2014-2015).
Principal Investigator: Dr. Gerard Tobias. This project is funded by the Technological Centre EURECAT and aims to produce composite materials at large scale.
COST Action TD1004: Theragnostics Imaging and Therapy: An Action to Develop Novel Nanosized Systems for Imaging-Guided Drug Delivery (2011-2015).
Dr. Tobias is involvedin the Management Committee of this COST Action that brings together the major European research groups working on the development of theragnostic (diagnostic/therapeutic) agents.
We are involved in several outreach activitiest targeting the non-scientific community, mainly through articles on popularization of science, interviews to newspapers, radio and television. Here are the links to some of them:
Dr. Tobias is a member of nanoDYF, a network for dissemination, outreach and training activities in Nanotechnology. For more information, visit:
The papers detailed below are some of the most recent publications from the group. Further references can be found under the “Publications” section:
M. Martincic, C. Frontera, E. Pach, B. Ballesteros, G. Tobias
Polyhedron DOI:10.1016/j.poly.2016.03.045 (2016)
Chemistry – A European Journal, 20, 11999-12003 (2014)
Reviews and Book chapters
Gerard Tobias, Emmanuel Flahaut. Smart carbon nanotubes, Smart materials for drug delivery (Royal Society of Chemistry), Vol. 2, p. 90-116 (2013). ISBN: 978-1-84973-552-0.
Gerard Tobias, Ernest Mendoza, Belén Ballesteros. Functionalisation of carbon nanotubes, Encyclopedia of Nanotechnology (Springer) Part 7, 911-919 (2012). ISBN: 978-90-481-9750-7.
If you are interested in these research topics do not hesitate to contact us at gerard.tobias_icmab.es