Ultra-sensitive biosensor could detect diseases in their earliest stages


May 27, 2012

The new ultra-sensitive biosensor has been demonstrated by detecting very small concentrations of Prostate Specific Antigen (pictured) (Image: EAS via Wikipedia)

The new ultra-sensitive biosensor has been demonstrated by detecting very small concentrations of Prostate Specific Antigen (pictured) (Image: EAS via Wikipedia)

A new ultra-sensitive test developed by scientists from the Imperial College London and Spain’s University of Vigo has the potential to detect the earliest stages of a disease, thereby giving any treatment the best possible chance of succeeding. The researchers claim their new biosensor test is capable of detecting biomarkers (molecules which indicate the presence of a disease) at concentration levels much lower than is possible with existing biosensors. While the new test has already proven capable of detecting a biomarker associated with prostate cancer, the team says their biosensor could be easily reconfigured to detect biomarkers related to other diseases or viruses.

The new biosensor consists of nanoscopic-sized gold stars suspended in a solution containing blood-derived proteins. Antibodies, which latch onto a biomarker when it is detected in a sample, are attached to the surface of the nanostars. In their study, the researchers used an antibody that latches onto Prostate Specific Antigen (PSA), a biomarker associated with prostate cancer. A secondary antibody, which has an enzyme called glucose oxidase attached to it, creates a distinctive silver crystal coating on the gold stars that can be detected through an optical microscope, thus signaling that PSA is present.

The researchers were able to detect PSA at 0.000000000000000001 grams per milliliter, which is comparable to the most sensitive biosensor tests currently available and significantly more sensitive than an existing Enzyme-linked Immunosorbent Assay (ELISA) test that can detect PSA at 0.000000001 grams per milliliter.

“Using current technology to look for early signs of disease can be like finding the proverbial needle in a haystack,” said Professor Molly Stevens from the Departments of Materials and Bioengineering at Imperial College London. “Our new test can actually find that needle. We only looked at the biomarker for one disease in this study, but we're confident that the test can be adapted to identify many other diseases at an early stage."

The researchers next plan to conduct further clinical testing to examine the potential of the new biomarker in detecting different biomarkers associated with HIV and other infections.

The team’s research was appears in the journal Nature Materials.

Source: Imperial College London

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

To bad they picked such a meaningless marker as PSA. Detecting it at ever lower levels is a good demo but useless medically. When you go for a PSA test you can't ride a horse or bike for a couple of days because will increase you PSA. Twice the urologist has thought my PSA level justified a needle biopsy and twice it has been negative. A needle biopsy is not that unpleasant but it is not with risk.

As I understand it, the man who invented the PSA test wishes he hadn't. It is just not a reliable marker for prostate cancer and most old farts like me should not treat their prostate cancer anyway.

Page Schorer

Needle biopsy isn't that great either. I had neutral psa level and a biopsy and neither one of them picked up my hi grade tumor. The earlier psa would at least allow early hormone therapy possibly negating the need for surgery. James O'Byrne May 29/12

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