Screening automation types

High-throughput screening automation exists at a variety of levels, from manual to semi-automated to fully automated turnkey systems (83). However, the types of equipment tend to be similar, and the way in which the screening process is integrated dictates the level of automation. For a brief discussion on the advantages and disadvantages of automated platforms versus workstations, see refs. 84 and 85. 

HTS is usually carried out it multiwell plates and the industry has settled on certain standard formats. One key standard is that most screening assays are carried out in 96 (8 12) or 384 (16 24) well plates with a standard footprint. This standard is important because most automation is optimized for use with these plates and attendant assay volumes in the 100 pL range. Furthermore, source plates containing test compound are typically stored in a similar configuration, allowing for more efficient transfer of test compound from the source plate to the assay plate. Various types of plates are available to match different assay formats, including... 

Many variations on the assay exist, but the ELISA, shown schematically below, is currently highly favored because of its simplicity once established in a laboratory sensitivity, detecting about one adduct per 107 bases and ability to screen many samples because of easy automations. The current prerequisite for the assay is that DNA can be modified to sufficiently high levels with the ultimate carcinogen to make it suitably antigenic. These types of antigens have been used to raise polyclonal antibodies in rabbits (41) and monoclonal antibodies from mice (42). 

The kitchen of a fast food restaurant is characterized by islands of automation, with well defined subprocesses focused on producing a certain kind of output, coordinated by a crew chief The principal advantage of a fast food restaurant is consistency and fast delivery. The dedicated subunits are designed to perform a certain type of process (assay) at a high rate with very little room for change. Economically, this model is difficult to sustain unless each assay type has sufficient demand to justify the existence of dedicated space, equipment and personnel. It is also not as efficient as a secondary screening model. For assays that are routinely, but not always, requested then this model is very appropriate (e.g., CACO-2 permeability, microsomal stability). However, for the more costly and complex assays that are requested less often, the cost of dedicated people and equipment is hard to justify and as a result the assay has to come off the menu. This is why most fast food restaurants have a relatively limited menu, including mostly foods that are simple to prepare. 

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