Nanotechnology could make lab test three million times more sensitive

Nanotechnology could be used to make a common type of lab test more sensitive, it has been found.

Researchers from Princeton University in America have published a study in the journal Analytical Chemistry which describes an improved lab test that uses nanotechnology. The new test could make a common lab test three million times more sensitive, which gives hope for earlier detection of certain cancers and Alzheimer's disease.

The new test is a fluorescent immunoassay, a laboratory staple for decades, and relies on antibodies that bind with specific proteins or biomarkers in a sample of fluid, such as blood or urine. The antibody specimens are labelled so that they emit fluorescence, which indicates that the target protein is present.

Researchers at Princeton have used an array of nano-antennas to amplify this type of fluorescence so that targeted proteins, such as the ones present in certain cancers, can be detected at much lower levels.

The process uses antenna arrays which consist of glass pillars measuring just 60 billionths of a metre in height, each capped with a tiny gold disk. There are also smaller gold dots attached on the sides of the pillars.

Senior author Stephen Y. Chou has compared the system to a wooden body of a violen, which transmits the vibrations of the strings to the surrounding air. Mr Chou is a professor of electrical engineering at Princeton, and explained "Without the body, you'd struggle to hear the sound."

Along with colleagues, Mr Chou evaluated the technology on fluid containing a standard lab protein called human immunoglobin G. They successfully detected the protein at a concentration three million times lower, which could mean that the test has future applications in the diagnosis of Alzheimer's disease, which researchers try to detect by taking samples of cerebrospinal fluid.

Yueming Li, a researcher at Memorial Sloan-Kettering Cancer Centre said that Mr Chou's technology, which detects much smaller concentrations in blood, "would be much easier and faster to use."

Posted by Fiona Griffiths