Tests to diagnose diseases early

Scientists have devised a new, ultra-sensitive test which they say could detect signs of a disease in its earliest stages.

Researchers at the Imperial College, London, said their new test can accurately detect particular molecules that indicate the presence of a disease, even when these are in very low concentrations. There are already tests available for some diseases that look for such biomarkers using “biosensors”. However, existing biosensors become less sensitive and predictable at detecting biomarkers when they are in very low concentrations, as occurs when a disease is in its early stages.

In the new study, published in journal Nature Materials, the researchers demonstrated that the new biosensor test can find a biomarker associated with prostate cancer, called Prostate Specific Antigen (PSA). However, the biosensor can be easily reconfigured to test for other diseases or viruses where the related biomarker is known, the researchers said.

Prof Molly Stevens, who led the research, said: “It is vital to detect diseases at an early stage if we want people to have the best possible outcomes — diseases are usually easier to treat at this stage, and early diagnosis can give us the chance to halt a disease before symptoms worsen.”

“However, for many diseases, using current technology to look for early signs of disease can be like finding the proverbial needle in a haystack,” Prof Stevens noted.

“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,” he added. To analyse the efficacy of their biosensor, the team used it to test PSA biomarker samples in solutions containing a complex mixture of blood derived serum proteins. It detected PAS at 0.000000000000000001 grams per millilitre, while the ELISA test, an existing method, could detect PSA at 0.000000001 grams per millilitre. Monitoring PSA levels at ultra-low concentrations can be crucial in the early diagnosis of the reoccurrence of prostate cancer, but classic detection methods are not sensitive enough to carry out this analysis with a high degree of accuracy, the researchers said.

The new test, the team said, could enable more reliable diagnosis, but more research will need to be done to further explore its potential.

The researchers now plan to carry out further testings to assess the efficacy of the biosensor in detecting a range of different biomarkers associated with conditions such as HIV and other infections.