Scientists have created a chemical nose that can sniff out cancers. The chemical nose can detect many types of cancers that are microscopic in size.

The sensor has gold nanoparticles and green fluorescent proteins that can differentiate between cancer cells and normal cells. Cancers that have metastasized or spread to various tissues can be identified.

"With this tool, we can now actually detect and identify metastasized tumor cells in living animal tissue rapidly and effectively using the 'nose' strategy. We were the first group to use this approach in cells, which is relatively straightforward. Now we've done it in tissues and organs, which are very much more complex. With this advance, we're much closer to the promise of a general diagnostic test," said Vincent Rotello at the University of Massachusetts Amherst.

The new cancer sensor was tested on mice that were developed to have a certain cancer that spreads throughout the body.

The cancer cells are now identified using the biological receptor approach. A drawback of using this approach is that it only works when one knows the cancer receptor beforehand. The new sensor eliminates this problem by using an array of gold nanoparticles and green fluorescent proteins -- a kind of a biological dye -- that assigns a different signature for each cancer type.

The researchers have said that the new sensor is similar to our nose. We can feel if something smells a bit odd because we know how that thing should smell. The new sensor can be taught the difference between a normal smell and a bad smell.

"Even though two cheeses may look the same, our noses can tell a nicely ripe one from a cheese that's a few days past tasting good. In the same way, once we train the sensor array we can identify whether a tissue sample is healthy or not and what kind of cancer it is with very high accuracy," said Rotello who led the research team that developed the sensor.

Rotello added that the sensor worked on a cancer sample size of around 2,000 cells - a microbiopsy - that's less invasive to the patients.

The sensor can differentiate between cancer cells that spread fast and those that spread slowly. And, it can detect cancer cells that are site-specific like breast cancer or prostate cancer.

The research team will be testing the sensor on human subjects in the next part of the study.

The research is published in the journal ACS NANO.