The development of acoustic levitation for time resolved protein crystallography experiments at XFELS
Docker P., Morris R., Newton M., Dye E., Kay J., Beale J., Axford D., Orville A., Stuart D.
This body of work is building on the systems described in a recent publication by Tsujino and Tomizaki . They describe the application of acoustic levitation to support protein crystals for X-ray diffraction experiments carried out at Synchrotron light sources. For clarity, a typical acoustic levitation system generates intense acoustic waves which are reflected back from a mirroring surface set at a distance matched to the frequency of sound being used. In air the reflected acoustic waves generate locations of minimum pressure or 'nodes' which act as wells for micron sized particles in the solution such as crystals. Multiple nodes can be generated and the nodes can also be made to process. This system can localise crystals periodically in air and therefore have enormous potential as a crystal sample delivery system. The system described in this work is a varient from this, described by Marzo et al and uses multiple transducers and there is no requirement for a mrror surface as the sound from multiple tranducers generates the accoustic trap. These acoustic traps also have the significant benefit of eliminating potential beam attenuation due to support structures or microfluidic devices. There is an additional need to eliminate sample environments when similar experiments are carried out using an X-ray Free Electron Lasers (XFEL) such as the LCLS at Stanford California as any sample environment would not survive the exposure to the X Ray beam. At an XFEL the Xrays are a billion times brighter than synchrotron radiation sources. The application for this system will be to exmine turn over in Beta lactomase proteins. The system will allow for diffraction data to be collected before and after turnover. For clarity this protein is responsible for bacteria becoming antibiotic resistant and there for of significant importance to future world health.