Stanford chemists develop ultra-sensitive test for diseases

The chemists said in San Francisco on Thursday that doctors may look for antibodies or related bio-markers out of the blood as the body's immune system mounts a response.

``This is while detecting a disease, whether it is cancer or infection by human immunodeficiency virus (HIV), which leads to acquired immune deficiency syndrome (AIDS).``The technique involves a molecule that the bio-marker will bind to.

``Through a series of specialised chemical reactions, known as an immunoassay, researchers can isolate an identifying "flag" adorned to the molecule, and the bio-marker bound to it, to provide a proxy measurement of the disease’’, they said.

The new technique was developed in the lab of Carolyn Bertozzi, a professor of chemistry at Stanford.

It augments the standard procedure with deoxyribonucleic acid (DNA) screening technology, by replacing the standard flag with a short strand of DNA.

This can then be teased out of the sample using DNA isolation technologies.

They said this is because the DNA screening is known to be far more sensitive than technologies used in traditional antibody detections.

The chemists said that by detecting the bio-markers of disease at lower concentrations, physicians could theoretically catch diseases far earlier in their progression.

The Stanford team noted in a study published in the journal ACS Central Science that they tested the new technique, with its signature DNA flag, against four commercially available tests approved by U.S. Food and Drug Administration for bio-marker 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 said that "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.

Meanwhile, the group announced winning grants to advance the technique into clinical trials, including a trial underway to help evaluate the technique as a screening tool for HIV.

They said early detection and treatment of the virus can help ensure that its effects on the patient are minimized and reduced the chance that it is transmitted to others.

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