Stanford chemists develop ultra-sensitive test for diseases

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.

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 technologies.

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."

The group has won a few grants to advance the technique into clinical trials, including a trial underway to help evaluate the technique as a screening tool for HIV. Early detection and treatment of the virus can help ensure that its effects on the patient are minimized and reduce the chance that it is transmitted to others.

The researchers are also pursuing tests for Type 1 diabetes, for which early detection could help patients manage the disease with fewer side effects. Endit