A fast way to measure biomarkers in the body could help in diagnosing prostate cancer, says a team of UK and US scientists. The test needs only a small amount of sample and takes less than three minutes to complete.

David Parker, at Durham University, led the team that developed the method, which measures levels of citrate and lactate in bodily fluids. These are important markers for disease, explains Parker. Anions such as citrate and lactate are formed in cell metabolism processes which alter when cancers grow - citrate levels in prostate fluid fall as prostate cancer progresses.

Lactate and citrate can be measured as they bind to europium complexes bringing about a change in luminescence

The team's measurements are derived from tests based on citrate and lactate anion binding to a series of luminescent europium complexes. The complexes showed different binding affinities for the anions, two with particularly good selectivity for either citrate or lactate. The researchers analysed changes in the complexes' emission intensities on binding and, by creating calibration curves relating anion levels to intensity, they could use the complexes' responses to samples to measure anion levels in fluids such as urine and prostate fluid.

The team compared its findings with results obtained using current enzyme methods of measuring citrate and lactate. These methods require longer sample preparation times and larger amounts of sample than Parker's sensing route, which showed similar results.

 A Prasanna de Silva, chair of organic chemistry at Queen's University Belfast, UK, explains that Parker's team has drawn on its experience of anion sensing with lanthanide complexes to create the systems, which respond differently to citrate and lactate. 'This is a convenient and quick method which provides early warning of prostate cancer which will bring relief to many men,' he says.

Parker says the work is currently being evaluated for commercial use. 'Ultimately this could form the basis of a simple screening procedure that could be carried out in local surgeries up and down the country,' he suggests.

Katherine Davies

Enjoy this story? Spread the word using the 'tools' menu on the left or add a comment to the Chemistry World blog.