Researchers from the University of Bath have found that nano-scale tubes made of carbon could be used to safely penetrate human cells and deliver anti-cancer medicines or modified DNA molecules for gene therapy.

Carbon nanotubes, which are just a billionth of a metre wide in diameter, are even found to occur in some pollutants in the ambient air or in soot for example.

Although there is a long way to go before the concept can undergo medical trials, a team led by Dr Sofia Pascu from the University's Department of Chemistry has shown how these tubes could be used as a 'cargo carrier', to break through the outer membranes of cells that some useful therapeutic molecules would otherwise be unable to enter.

They could also be used to carry imaging agents such as fluorescent tags and radionuclides (radioactive isotopes widely used in therapy and diagnosis) that would make it possible to obtain better images of cells and tissues and so aid earlier detection of cancers.

The technique developed by the team has involved shortening, modifying and purifying carbon nanotubes so that they are far less harmful to cells than the commercial nanotubes. Glowing, fluorescent molecules are then wrapped very tightly around them using an innovative, rapid, highly controllable and low-cost process based on the techniques of "supramolecular chemistry", a branch of chemistry coined as chemistry beyond the molecule. Early indications show that prostate cancer cells might absorb the nanotube/molecule assemblies particularly well.

Next steps for the research team include looking at how the nanotubes could be developed not only to carry a medically useful cargo both inside and outside the tube, but also to target specific cells (particularly damaged or cancerous ones).

Further work will also include devising a simpler way of ensuring a strong attachment between molecules and nanotubes so that the molecules can penetrate the cell membrane successfully without becoming dislodged first.

The Bath research team includes researchers from several disciplines: Dr Dan Pantos and Gabriele Kociock-Kohn (Department of Chemistry), Professor Rex Tyrrell (Department of Pharmacy & Pharmacology), Dr Justin O'Byrne (Department of Chemical Engineering) and two PhD students in Chemistry, Zhiyuan Hu (ORS scholar 2008-2011) and Rory Arrowsmith.

This pioneering work has been carried out by the University of Bath team in collaboration with the Lasers for Science Facility at the Research Complex at Harwell, and also involves the Universities of Oxford, Cambridge and Nottingham. It is being funded by the Medical Research Council, the Royal Society and the University of Bath.

Details on the team's work to date have been published in the February issue of the journal 'Advanced Functional Materials'.

Health Canal