World of Temperature
Similarly, Dr. Scott Busby of Novartis (Cambridge, MA) developed a matrix-assisted laser desorption ionization/high-throughput screening (MALDI/HTS) platform built around the Autoflex Speed™ MS (Bruker, Billerica, MA). This is used to screen a million-well small-molecule library and products from several enzymatic assays. Throughput is 80,000 wells/ day from 1536-well plates. Results were validated with comparable bridg- ing studies with traditional, and much slower, LC/MS screens. MS-based screens appear to be more quantitative than fluorescence microscopes that so dominate the high-content analysis (HCA) market segment. Scott also offered that the waste stream from the lab was over 50 lb/day, which was a continuing issue.
Pipetting: The key to improving data quality Discovery and development programs often involve comparing data
from several sources, which use different instruments. Comparisons are more meaningful if the data are accurate and precise. Usually the largest contribution to %CV, typically 80%, is traced to the analyst. Humans get bored, fatigued, sloppy, or distracted. Since most assays are run in liquids, liquid manipulation by pipetting is common.
Other factors affecting pipetting performance were discussed in five post- ers from Artel (Westbrook, ME), including one on measuring nanoliter drops (
www.artel-usa.com/news-events/slas/). A vendor tutorial by Keith Albert of Artel and Nat Hentz of North Carolina State University (Raleigh) demonstrated the effect of inaccurate pipetting on assay performance using two assay models. Each model consisted of three components, whereby the volume of each component was intentionally adjusted by ±10%. The impact of the variability was measured by comparing result- ing IC50
measured by %RSD on IC50
potency curves. The poster addressed the effect of imprecision as values as determined by plotting activity versus
concentration. The results strongly suggest that liquid handler variability affects assays. In other words, the resolution between higher-potency compounds is decreased and, likewise, important chemical scaffolds can be missed for lower-potency inhibitors. Plus, if one has a poorly performing liquid transfer in a serial dilution, errors are compounded, producing compound concentration inaccuracies larger than 50%. Thus, good practice requires properly calibrating the equipment and logging all pertinent information, including reagents, lots, instruments, protocols, and staff involved.
Pipetting workstation The new PIPETMAX® from Gilson (Middleton, WI) is a nine-plate-capacity
liquid handler designed specifically to maximize reproducibility with low- to medium-throughput assays. The liquid handler part utilizes Gilson’s time-proven PIPETMAN® single- or multichannel pipet. Setting up the PIPETMAX is very easy, with a master nine-position deck that can be loaded with source and target multiple-well plates. One opens the top, removes the old deck, and sets the new deck in place. The clear plas- tic lid is closed for operation. This keeps out probing hands and reduces environmental effects. The PIPETMAX is described in more detail at
http://www.americanlaboratory.com/914-Application-Notes/157002- The-Scales-of-Scientific-Justice-in-Translational-Science-Data-Repro- ducibility-and-Verifiable-Science/.
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AMERICAN LABORATORY • 5 • JUNE/JULY 2014
2014-05_WOT-PRESTO-A80_3x9_US_AmLab.indd 1 23.05.2014 08:40:01
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