Scientists at Princeton University have made tests to detect diseases, like cancer and Alzheimer's disease, 3 million times more sensitive by using nanotechnology.

The breakthrough could enable doctors to detect these illnesses at much earlier stages, when they are more treatable.

"This advance opens many new and exciting opportunities ... in disease early detection and treatment," said Stephen Chou, a Princeton engineering professor, who led the research team. "You can have very early detection with our approach."

Researchers adapted a biological test called an immunoassay, which measures the concentration of a substance in a body fluid sample and is used to find markers for cancers and Alzheimer's, in patients.

The test produces a fluorescent glow when the disease is detected. The stronger the presence of the disease, the brighter the test glows.

The glow can't be detected if only faint, early-stage, traces of the disease are present and the disease could be missed.

The researchers at Princeton used nanotechnology to amplify the fluorescence, so the test now can detect disease with 3 million times fewer disease biomarkers present.

The key to the breakthrough, according to Princeton's researchers, lies in a new nanomaterial they call D2PA. The nanomaterial, which was developed in Chou's lab, consists of a thin layer of gold nanostructures surrounded by glass pillars that are 60 nanometers in diameter.

The pillars boost the collection and transmission of light by a billion-fold, Princeton said.

About 1,000 of the pillars can be laid side-by-side and still only be as wide as a human hair.

Chou is focused on using the new technology to detect early-stage breast and prostate cancers.

He also is working with researchers in New York to develop tests to detect proteins associated with early stage Alzheimer's disease.