October 29, 2012
Researchers at the Imperial College of Science, Technology and Medicine, London, United Kingdom, have developed a test to detect viruses and disease biomarkers. This new test is reported to be 10 times more sensitive than the best available today. Researchers Roberto de la Rica and Molly Stevens were able to detect an HIV biomarker called p24 in blood samples as well as low levels of prostate specific antigen (PSA), an early indicator for prostate cancer. The test can be reconfigured to detect known biomarkers of other viruses and diseases. De la Rica noted that the test will enable previously undetectable HIV infections and indicators of cancer to be picked up.
The biosensor analyzes serum derived from blood in a disposable, transparent container. The enzyme label of an enzyme-linked immunosorbent assay (ELISA) controls the growth of gold nanoparticles and generates colored solutions. If the marker is present, the reaction generates irregular clumps of nanoparticles that give off a blue color in the solution. If it is absent, the nanoparticles separate into ball-like shapes that give off a reddish color. These reactions can be seen with the naked eye.
De la Rica states that this test could be significantly cheaper than those presently being used, and may result in more widespread HIV testing in developing countries. The team plans to approach not-for-profit global health organizations for assistance to develop and manufacture the test for distribution, particularly in low-income countries.
The study titled, "Plasmonic ELISA for the Ultrasensitive Detection of Disease Biomarkers with the Naked Eye," was published online in the journal Nature Nanotechnology, 28 October 2012; DOI:10.1038/nnano.2012.186.