Cancerous tumours can be detected under the skin by using tiny gold particles embedded with dyes, a new study claims.
Scientists at Emory University and the Georgia Institute of Technology said the new technique could one day help doctors to detect and diagnose cancer earlier and less invasively.
The researchers injected mice with gold particles studded with antibody fragments called ScFv peptides that bind cancer cells.
They found that the particles grab on to tumours, and when illuminated with a laser beam they send back a signal that is specific to the dye.
Writing in the journal Nature Biotechnology, the scientists say the cancer cells were detected at a depth of 1cm to 2cm, making the gold particles an especially appropriate tool for head and neck tumours that tend to be more accessible.
They argue that the treatment will need further adaptation before it can be used for lung or abdominal cancers deep within the body.
The gold particles are extremely bright and are about 60 to 80 nanometres in diameter - thousands of times smaller than a human hair.
'I expect that with these probes it will be possible to detect cancer much earlier, at the microscopic level,' said Dr Dong Moon Shin, associate director of Emory's Winship Cancer Institute.
'Even a half-centimetre-wide nodule contains millions of cancer cells, but with this technology we can detect many fewer cells at a time.'
The researchers now plan to modify the coatings of the nanoparticles to improve tumour targeting. They hope that the gold particles could also be used to selectively deliver drugs to cancer cells.
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