Tiny golden bullets could help tackle asbstos-related cancers

Tiny golden bullets could help tackle asbstos-related cancers

Gold nanotubes – tiny hollow cylinders one thousandth the width of a human hair – could be used to treat mesothelioma, a type of cancer caused by exposure to asbestos fibres, say researchers.

In a study published today in the scientific journal Small, the researchers demonstrate that once inside the cancer cells, the nanotubes absorb light, causing them to heat up, thereby killing the cells.

The work is the result of collaboration between scientists at the University of Leeds and University of Cambridge.

More than 2,600 people are diagnosed in the UK each year with mesothelioma, a malignant form of cancer caused by exposure to asbestos fibres. Although the use of asbestos is outlawed in the UK now, the country has the world’s highest levels of mesothelioma because it imported vast amounts of asbestos in the post-war years.

The global usage of asbestos remains high, particularly in low- and middle-income countries, which means mesothelioma will become a global problem.

“The next stage will be to load these nanotubes with medicines for enhanced therapies.”

The researchers say mesothelioma is one of the ‘hard-to-treat’ cancers – and there is a need for new, effective treatments.

They have developed a form of gold nanotubes whose physical properties are ‘tunable’ – in other words, the team can tailor the wall thickness, microstructure, composition, and ability to absorb particular wavelengths of light.

During experiments, the researchers added the nanotubes to mesothelioma cells cultured in the lab and found that they were absorbed by the cells. When the team targeted the cells with a laser, the nanotubes absorbed the light and heated up, killing the mesothelioma cell.

Professor Stefan Marciniak, from the Cambridge Institute for Medical Research, said: “The mesothelioma cells ‘eat’ the nanotubes, leaving them susceptible when we shine light on them. Laser light is able to penetrate deep into tissue without causing damage to surrounding tissue. It then gets absorbed by the nanotubes, which heat up and, we hope in the future, could be used to cause localised cancer-cell killing.”

The scientists will be developing their work further to ensure the nanotubes are targeted to cancer cells with less effect on normal tissue.

Manufacturing gold nanotubes

The nanotubes are made in a two-step process. First, solid silver nanorods are created of the desired diameter. Gold is then deposited from solution onto the surface of the silver. As the gold builds-up at the surface, the silver dissolves from the inside to leave a hollow nanotube.

The approach advanced by the Leeds team allows these nanotubes to be developed at room temperature, which should make their manufacture at scale more feasible.

Professor Stephen Evans, from the School of Physics and Astronomy at the University of Leeds, said: “Having control over the size and shape of the nanotubes allows us to tune them to absorb light where the tissue is transparent and will allow them to be used for both the imaging and treatment of cancers.

“The next stage will be to load these nanotubes with medicines for enhanced therapies.”

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