One of the most common substances used for doping is EPO (erythropoietin), which is difficult to detect. In an era when there are increasing numbers of 'copies' of biotechnologically produced medications (biosimilars), it is also becoming more and more difficult to detect the difference between the body's own EPO and that made biosynthetically. Chemists at Vienna University of Technology (TU) working jointly with ARC Seibersdorf, are developing a new analytical method, based on MALDI mass spectrometry, to track down the perpetrators of doping.
"With the aid of MALDI mass spectrometry, a method that is used for non-destructive desorption/ionisation of large molecules, especially biopolymers, we compare the deceptively similar 'humanised' form of EPO with the body's own substance. The two samples differ in the structure of the amino acid chains and/or in that of the associated sugar chains. Depending on the structure of these sugar chains and where they bind to, we can recognise whether this is a natural or biosynthetic EPO", explains Professor Günter Allmaier of the Institute of Chemical Technologies and Analytics at Vienna University of Technology.
Previous methods, for example isoelectric focusing, exhibit several weaknesses. First, it takes between two and three days to obtain the test results. Furthermore, the method is regarded as difficult to automate, and is based on antibodies which can detect EPO in urine but sometimes are too non-specific and do not distinguish the structure sufficiently precisely. Allmaier and his co-workers are concentrating now on a search for suitable analytical strategies that can detect recombinant EPO directly in urine. Lab-on-chip technology is to be combined with laser-based time-of-flight mass spectrometry. Following the testing phase, Allmaier estimates that the method may reach the patentable stage around 2009 and provide a valuable support in the fight against doping. Allmaier: "The most essential point in our strategy is that we are developing a method with which the EPO molecule itself is detected. All the other methods used so far have been indirect."