In situ diffraction experiments at the Nagoya University BL2S1 beamline

Microfluidic-based sample handling devices are emerging from the recent methodological developments toward room temperature data collection at most X-ray diffraction beamlines. Based on the general availability of extremely fast X-ray detectors, it is nowadays becoming common practice to collect data in a fully automated manner, with all frozen samples handled by robots during the synchrotron experiments. With all the high-throughput data collection strategies operated at the beamlines, the next bottleneck of the automated pipeline for protein crystallography becomes the preparation of samples in sufficient amounts to fulfill the capacity for data collection.

The overall time to collect one full data set is becoming shorter, and the number of samples per amount of time increases, which affects the required human labor for producing these crystals. The emergence of in situ data collection strategies partly solves this problem, as sample crystals are not cryo-preserved but rather exposed in the same condition in which they grew. If properly implemented, this approach has great advantages for motivating the recording of many more samples in a quick and efficient manner. Eventually, it will then be needed to make fully automated and integrated systems in which samples will not be physically touched by human beings anymore.

In the current presentation, we will compare two different approaches which we spent time implementing at the Nagoya University beamline BL2S1 of the Aichi Synchrotron. First, sample crystals were prepared directly in a 3D- printed crystallization plate that is directly adaptable for diffraction experiments with a minimum of human intervention. The second approach takes advantage of microfluidic for the preparation and handling of the crystals. At Aichi Synchrotron, full data sets could be recorded on single crystals directly at room temperature without the requirement for merging data sets. Both techniques have been developed with the goal to be able to experiment at any of the Japanese synchrotrons, requiring no modifications of the sample environments at the beamlines.