Stanford chemists develop ultra-sensitive test for diseases
13 March 2016, Nirapad News: A team of chemists at Stanford University has developed a new technique, presumably thousands of times more sensitive than current methods in laboratory experiments, to detect cancers and other diseases.
In detecting a disease, whether it is cancer or infection by human immunodeficiency virus (HIV), which leads to
acquired immune deficiency syndrome (AIDS), doctors may look for antibodies or related biomarkers out of the blood as the body’s immune system mounts a response.
The technique involves a molecule that the biomarker will bind to. Through a series of specialized chemical
reactions, known as an immunoassay, researchers can isolate an identifying “flag” adorned to the molecule, and the
biomarker bound to it, to provide a proxy measurement of the disease, reports Xinhua.
The new technique, developed in the lab of Carolyn Bertozzi, a professor of chemistry at Stanford, on the U.S. west
coast, augments this standard procedure with deoxyribonucleic acid (DNA) screening technology, by replacing the
standard flag with a short strand of DNA, which can then be teased out of the sample using DNA isolation
DNA screening is known to be far more sensitive than technologies used in traditional antibody detections. And by
detecting the biomarkers of disease at lower concentrations, physicians could theoretically catch diseases far
earlier in their progression.
In a study published in the journal ACS Central Science, the Stanford team said they tested the new technique, with
its signature DNA flag, against four commercially available tests approved by U.S. Food and Drug Administration
(FDA) for a biomarker for thyroid cancer.
It outperformed the sensitivity of all of them, by at least 800 times, and as much as 10,000 times. Peter Robinson,
a co-author on the study and graduate student in Bertozzi’s group, said “the thyroid cancer test has historically
been a fairly challenging immunoassay, because it produces a lot of false positives and false negatives, so it
wasn’t clear if our test would have an advantage … We suspected ours would be more sensitive, but we were
pleasantly surprised by the magnitude.”