Canadian researchers have devised a way to assess biological samples for the presence of multiple small molecules, which has profound implications for the rapid identification of diseases.

Being able to distinguish diseased cells from healthy ones is vital in the identification of diseases in humans. A rapidly advancing way of doing this is to determine the concentrations of small molecules (biomarkers) present in biological samples, as amounts of these chemicals differ between diseased and healthy cells. Vladimir Baranov and colleagues from the University of Toronto have now developed a sensitive method that, by using lanthanide ions, is able to determine the concentrations of many biomarkers at once. This, they say, will have important applications in clinical diagnostics.

Baranov and colleagues bound ¹⁵¹Eu ions to a polymer chain chemically attached to an antibody, which itself binds to a natural biomarker. Once the unreacted antibody derivative is washed away, the sample is exposed to inductively coupled plasma mass spectrometry. This atomises the entire sample and allows the elemental composition to be determined. In this case, the amount of ¹⁵¹Eu correlates to the amount of biomarker present in the original sample. The number of ¹⁵¹Eu ions within each molecule means that the method is more sensitive to the amount of biomarker than existing techniques, said Baranov.

The power of the team's method is that it can measure many biomarkers simultaneously, simply by using a different one of the 50-plus stable lanthanide isotopes for antibodies against different targets. Baranov's team are now working to apply their technique to the classification of leukaemia samples.

The importance of this research is emphasised by Les Ebdon, Vice-Chancellor of the University of Bedfordshire, UK, who said 'This exciting study ... promises to advance our abilities to understand and diagnose complex diseases such as leukaemia.'

David Barden