Gold makes cancer diagnosis faster

A study on mice has suggested that gold nanoparticles may make diagnosis of cancer faster and less invasive.

The researchers have shown that by using tiny gold particles embedded with dyes, they could identify tumours under the skin of a living animal, which may lead to earlier detection of cancer.

Lead researcher Dr. Shuming Nie, a professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, says that the gold particles, when interspersed with antibody fragments called ScFv peptides that bind cancer cells, grab onto tumours after being injected into the body.

The scientist says that the tumour-bound particles, when illuminated with a laser beam, send back a signal that is specific to the dye.

"This is a new class of nanotechnology agents for tumour targeting and imaging," Nature Biotechnology quoted Dr. Nie as saying.

The scientists were in the process of developing light-emitting semiconductor crystals called 'quantum dots' into tools for cancer detection and treatment for several years.

According to Dr. Nie, colloidal gold (gold particles in suspension) are more beneficial as compared to quantum dots in the sense that gold appears to be non-toxic and the particles produce a brighter, sharper signal.

"The detail is like a fingerprint, and because of the enhancement provided by the gold surface, the signal from the dye tags is very bright," he said.

The researchers also said that the distinct peaks in the dye signal meant that various probes could be used at the same time.

"The tags' rich spectroscopic signatures provide the capability of using several probes at once, but that will require more sophisticated computational tools," said Dr. May Dongmei Wang, assistant professor of biomedical engineering and director of biocomputing and bioinformatics in the cancer nanotechnology center.

He added: "We are developing data processing tools and making them available to the National Cancer Institute's caBIG (cancer biomedical informatics grid) so that the research community can use them."

Dr. Nie indicated that while colloidal gold was used in the safe treatment of people with rheumatoid arthritis for several decades, they were still studying the toxicity of quantum dots, which contain the heavy metal cadmium, and their long-term fate in the body.

The researchers revealed that the gold particles were particularly appropriate tools for gathering information about head or neck tumours, which tend to be more accessible.

However, the technology needs to be adapted further for use with abdominal or lung cancers deep within the body.

Dr. Nie revealed that his lab was planning to modify the coatings of the nanoparticles to improve tumour targeting. He said that eventually the gold particles could also be used to deliver drugs to cancer cells selectively.