Researchers use nanotechnology to greatly increase sensitivity of biological test

Princeton researchers have developed a way to make a common biological test more than 3 million times more sensitive. The greatly increased performance of the test, called an immunoassay, could lead to much earlier detection of cancer, Alzheimer’s disease and other disorders. Immunoassays mimic the action of the immune system to detect the presence of biomarkers, the chemicals associated with diseases. The test produces a glow that can be measured in a laboratory, but sometimes the glow is too faint to observe due to low levels of the markers. The researchers have used nanotechnology to greatly amplify the faint fluorescence. They were able to drastically increase the fluorescence signal by fashioning glass and gold structures that are so small they could only be seen with a powerful electron microscope. Compared to a conventional immunoassay, the enhanced immunoassay would require 3 million times fewer biomarkers to be present in a sample.