University physicists in Germany are working with a healthcare company to speed up the analysis of DNA

When Jochen Feldmann, a physicist at Ludwig-Maximilians-Universität (LMU) in Munich, began studying the optical properties of gold nanoparticles, he soon realized that they could provide information about their environment. He thought the nanoparticles might be useful for sensing, so he contacted Roche Diagnostics and the result was a long-running collaboration between the Photonics and Optoelectronics Group at LMU and the healthcare company to detect and manipulate biological molecules such as DNA.

The collaboration's latest research project, funded by the Bavarian Science Foundation and the German Science Foundation, involves the use of gold nanoparticles as 'nanostoves' to speed up the melting of double strands of DNA into single strands for analysis (Nano Lett. 8, 619; 2008). To do this, the researchers fire a laser at large aggregates of gold nanoparticles bound together by strands of DNA. The nanoparticles directly transfer energy from the laser to the DNA, causing the strands to split. As an added bonus, the nanoparticles can 'report' that the DNA has melted because their optical properties change when they break free of the aggregate. Moreover, the whole process takes just a few microseconds, compared with minutes for previous techniques.

In addition to a string of papers, two of the postdocs who worked on the collaboration — Carsten Sönnichsen and Thomas Klar — are now professors with their own groups. So what is the secret of a successful collaboration? “The most important thing is to find the right partners from other fields and work together as open-minded specialists,” says Feldmann. “Indeed, I cannot think of a current project in our group that is not multidisciplinary. Synthetic chemistry and biochemistry now play a central role in our work, with physicists and experienced chemists using the same coffee machine.”