Screening automation incubators

All the high-throughput screening automation platforms tend to have the same limited number of basic operations a method moving around microplates, dispensing liquids, a series of detectors, and incubators. The methods... 

Korfmacher, W. A. et al. 1999. Development of an automated mass spectrometry system for the quantitative analysis of liver microsomal incubation samples A tool for rapid screening of new compounds for metabolic stability. Rapid Commun. Mass Spectrom. 13 901. 

COS-7 or CHO cells (for initial transfection screening) or cells of therapeutic interest (e.g., dendritic cells and various cancer cells) at a confluence of 50%, grown in 96-well culture plates, were placed into the robot by the robotic conveyor. In a fully automated process, the robot removes the lid from the cell culture microtiter plate, dispenses lipoplexes into the wells (triplicates), replaces the lid and returns the plate to the incubator. After four hours, the cells are automatically retrieved, the cell monolayers are carefully washed using a special drop mode of the integrated plate washer, fresh medium is added, and the cells are incubated for further 42 hours before harvesting. 

An example for an automated stability test in plasma is described by Linget and du Vignaud (1999). Incubations are performed on a 215 Gilson liquid handler. Incubation was done at substrate concentrations of 50 pM on 96 deep well plates. Each incubation tube contained 375 pL of a 200 pM test compound solution (in 0.1 M Tris buffer with 3% BSA, added to assist dissolution of compounds with poor solubility) and 1125 pL of plasma. Samples are taken after incubation times of 0, 1, 2, 3, 4 and 5 min. At each of these time points an aliquot of the incubation mixture was transferred from the incubation tube into a well in a 96 deep well plate containing an equal volume of acetonitrile for quenching by protein precipitation followed by centrifugation of the plates. Supernatants were analyzed by HPLC for metabolic screening. 

One of the most important advantages of these methods is their sensitivity. Generally, these methods measure submicrogram quantities of the insecticide in question and are more sensitive than most chemical methods. Moreover, enzymatic methods can detect insecticides that are converted into metabolites with a high inhibitory potency. Enzymatic methods can be simple and rapid. Automated analyses, for example, provide simple high-precision techniques with short incubation periods, high sensitivity, and adaptability to routine analyses. As mentioned previously, such methods are invaluable as screening techniques. 

K. Lin, C-C. Elicone, C. Liu, C. Duchoslav, E. Development of an Automated Mass Spectrometry System for the Quantitative Analysis of Liver Microsomal Incubation Samples A Tool for Rapid Metabolite Screening of New Compounds for Metabolic Stability, Rapid Commun. Mass Spectrom. 13, 901-907 (1999). 

These automated assays can be used for high-throughput ADME screening in early drug discovery. The double-sink PAMPA permeability assay mimics in vivo conditions by the use of a chemical sink in the acceptor wells and pH gradient in the donor wells. The use of the pION gut-box integrated on the deck has shortened the PAMPA assay incubation time to 30 minutes. The permeability coefficient and rank order correlate well with data obtained using the in vitro Caco-2 assay and in vivo permeability properties measured in rat intestinal perfusions. 

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