Novel nanoparticles can help detect cancer without biopsy

Scientists have developed nanoparticle-based imaging technique that can detect various types of breast cancer, and other diseases, without the need for extracting tissue samples from the patient.

The research, published in the journal Nature Nanotechnology, opens up a new avenue in minimally invasive disease diagnosis.

"The use of nanoparticles for bio-imaging of disease is an exciting and fast-moving area of science," said Yiqing Lu from Macquarie University in Australia.

"Specially designed nanoparticles can be placed in biological samples or injected into specific sites of the body and then 'excited' by introduced light such as that from a laser or an optical fibre," Lu said.

"Disease biomarkers targeted by these nanoparticles then reveal themselves, by emitting their own specific wavelength signatures which are able to be identified and imaged," he said.

A major limitation however is that only a single disease biomarker at a time is able to be distinguished and quantified in the body using this type of detection technique.

"The tissue environment is extremely complex - full of light absorbing and scattering elements such as blood, muscle and cartilage. And introducing multiple nanoparticles to a site, operating at multiple wavelengths to detect multiple biomarkers, produces too much interference," Lu said.

"It makes it extremely difficult to determine accurately if a range of disease biomarkers are present," he added.

Researchers solved this issue has been to engineer innovative nanoparticles that emit light at the same frequency (near infrared light) but that are able to be coded to emit light for set periods of time (in the microsecond-to-millisecond time range).

"It is the duration of the light-emission and the biomarker reaction to this timed amount of light that produces a clearly identifiable molecular signature," Lu said.

"This enables high-contrast optical biomedical imaging that can detect multiple disease biomarkers all at the one time," he said.

In laboratory testing, the innovative nanoparticles have been able to detect multiple forms of breast cancer tumours in mice.

"We were able to successfully detect and identify key biomarkers for a number of different sub-types of breast cancer," said Fan Zhang at Fudan University in China.

"This technique has the potential to provide a low-invasive method of determining if breast cancer is present, as well as the form of breast cancer, without the need to take tissue samples via biopsy," Zhang said.

"Ultimately our novel nanoparticles will enable quantitative assessment for a wide range of disease and cancer biomarkers, all at one time. The technique will be able to be used for early-stage disease screening and potentially utilised in integrated therapy," said Zhang.