Abstract
An automatic sample changer system for measurements of large numbers of liquid samples - the µDrop Sample Changer - is presented. It is based on a robotic arm equipped with a pipetting mechanism, which is combined with a novel drop-based sample holder. In this holder a drop of liquid is suspended between two parallel plates by surface tension. The absence of a transfer line benefits the cleaning, improving the background as well as making it faster and more efficient than most comparable capillary-based systems. The µDrop Sample Changer reaches cycle times below 35 s and can process up to 480 samples in a single run. Sample handling is very reliable, with a drop misplacement chance of about 0.2%. Very low sample volumes (<20 µl) are needed and repeatable measurements were performed down to 6 µl. Using measurements of bovine serum albumin and lysozyme, the performance of the instrument and quality of the gathered data of low and high concentrations of proteins are presented. The temperature of samples can also be controlled during storage and during measurement, which is demonstrated by observing a phase transition of a mesophase-forming lipid solution. The instrument has been developed for use in small-angle X-ray scattering experiments, which is a well established technique for measuring (macro-)molecules. It is commonly used in biological studies, where often large sets of rare samples have to be measured.
Highlights
Synchrotron beamlines are the preferred alternative when many samples are to be measured with X-ray techniques in a short time
An automatic sample changer system for measurements of large numbers of liquid samples – the mDrop Sample Changer – is presented. It is based on a robotic arm equipped with a pipetting mechanism, which is combined with a novel drop-based sample holder
Manual sample exchange is slow and tedious, generally requires more sample volume than strictly necessary for a measurement, and is prone to mistakes by the experimenter. Automation of this process is more efficient with respect to time and sample volume, and leads to more reliable and repeatable measurements
Summary
Synchrotron beamlines are the preferred alternative when many samples are to be measured with X-ray techniques in a short time. The high brilliance of synchrotrons limits the maximum exposure duration due to radiation damage, which is often a problem with biological samples (Kuwamoto et al, 2004). Manual sample exchange is slow and tedious, generally requires more sample volume than strictly necessary for a measurement, and is prone to mistakes by the experimenter. Automation of this process is more efficient with respect to time and sample volume, and leads to more reliable and repeatable measurements. These criteria are essential in particular for small-angle X-ray scattering (SAXS) measurements of biological samples (BioSAXS). In structural biology BioSAXS has become a frequently used technique, due to the development of new analysis methods, the use of
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
