X-rays to reveal life´s inner secrets

At present, no form of particle radiation can be used to depict individual viruses and molecules. However, research at Uppsala University has awakened new hopes that, with a ‘free-electron laser´, pictures of the tiniest components of matter will become possible.

‘ Our goal is to develop an X-ray source of ultra-high intensity and with extremely short pulses,´ explains Professor Janos Hajdu, who heads the research group at Uppsala University.The researchers´ idea is to attempt to create a picture of the sample before it is affected by the radiation energy. To achieve this, they plan to bombard the sample with massive quantities of photons (light quanta) for a fleeting instant of time.‘This is in line with the laws of physics. But it´s never been tried in practice, since the powerful pulses don´t occur naturally on Earth.´

With the new technology, the researchers hope to succeed in obtaining pictures of individual viruses and macromolecules. Janos Hajdu and his research colleague David van der Spoel envisage several future fields of application for this X-ray technology. One is the design of anti-HIV drugs based on knowledge, which the technology may provide, of the structure of this virus. Extreme states are another field.‘It may be possible to create conditions here on Earth that otherwise exist only in black holes.´

Practical testing
The research in Uppsala has created a great stir outside Sweden.

‘ It´s made it financially practicable to realise plans for this type of free-electron laser facility. The first unit of this kind is expected to be completed in the USA in 2009, and in 2012 a similar one will be commissioned in Germany,´ relates Janos Hajdu.The next stage will be to use the equipment in practice. The new Swedish Research Council initiative will enable the Uppsala group to conduct the research themselves. This is not to say that the researchers will not collaborate with other groups in the world.

‘We can´t do everything on our own. To grasp how the process works in detail, we need to collaborate with experts from various fields, such as plasma physicists and atomic physicists.´

As yet, the researchers´ ideas have yet to be tried out in practice. But Janos Hajdu is convinced that the new X-ray technology will have a major bearing on research.

‘ If everything works as we think it will, we´ll create a new field in biology. If it doesn´t go according to plan, it´s just new physics — that is, the physics won´t work out as we expect.´

Peter Tillhammar

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xray.bmc.uu.se/molbiophys