research papers
In order to perform X-ray crystallographic analysis, protein crystals are removed from their growing solution by means of a nylon loop, which is then mounted on a goniometer. As this process is repeated for a large number of crystals, there is a need for automation, especially with regard to the placement on the nylon loop. A novel technique involving the use of acoustic radiation forces and a micro-machined fluidic device is introduced here. After insertion into the micro-machined channel, the crystals are positioned in a row along its centre-line by excitation of a high-frequency standing pressure field, and then moved towards an orifice by applying a flow along the channel, which also ensures spatial separation. Once located in a defined orifice, the single crystals can be removed using a nylon loop. X-ray crystallographic analysis showed that application of ultrasound does not influence the diffraction properties of the crystals.
Keywords: acoustics; acoustic radiation forces; ultrasound; microfluidics; nylon loops; insulin crystals; porcine insulin; crystal manipulation.
Supporting information
Portable Document Format (PDF) file https://doi.org/10.1107/S0021889809019177/he5444sup1.pdf | |
AVI file https://doi.org/10.1107/S0021889809019177/he5444sup2.avi |