Laser tweezers to lead to faster breakthroughs in biological research
A novel process for selecting and examining protein microcrystals
A novel process for selecting and examining protein microcrystals, which can be essential for understanding biological functions, is expected to save precious research days and resources and lead to faster breakthroughs in healthcare. Protein microcrystals enable researchers to analyse the structure of molecules and how they behave, for example in disease, but can take a long time to prepare and analyse. A new process for using laser ‘tweezers’ developed at the Rutherford Appleton Laboratory will help streamline crystal selection. The results are published in Acta Crystallographica D this week.
The technique allows researchers to select and place microscopic protein crystals on customised sample holders for crystallographic analysis on the world leading Microfocus MX beamline (I24). This beamline is renowned for its tiny and flexible beamsize, which can be adjusted to match the samples' characteristics for optimised data collection.
The new laser ‘tweezers’ technique is the result of a cross-campus collaboration between Diamond and STFC’s Central Laser Facility (CLF) and Technology departments. In this area of research, crystals of proteins rather than single molecules must be used, but for many proteins, the crystals formed can be so small (less than 10 microns) that they are very difficult to handle and mount onto standard sample holders for analysis. This can lead to some potentially vital crystals being discarded. STFC’s Technology Department helped to overcome this problem by weaving a microfiber web to create a ‘net’ for the crystals to be mounted on. A laser is then used to grab the minute crystals and move them onto the novel sample holders in the process of laser tweezing.
The picture to the right shows a 10 micron crystal placed, using laser light, onto a 50 micron square aperture backed with microfibres ready for freezing and X-ray diffraction studies.
Armin Wagner, Principal Beamline Scientist for I23 and project lead at Diamond, on why this technique is so important.
Andy Ward at the Central Laser Facility said: “This is a great example of how scientists from different facilities at the Rutherford Appleton Laboratory collaborate to address challenging problems. It’s clearly a benefit to have them all on one site here at the Harwell campus”.