Workstations

Earlier we defined a workstation as a device that performs multiple different functions. The first workstation was the Benchmate™ from Zymark. This versatile workstation has a dedicated robot arm with a gripper that can move containers to and from different locations on its workbench. Several devices are integrated, such as a precision balance, a single-channel canule for sample transfer, reagent addition, and dilutions, a vortexer, and a HPLC injector. It uses the cylindrical work envelope that is typical of the Zymate architecture that also enables the integration of additional external devices. The Benchmate has also been developed for areas in biopharmaceutical R&D where quality control and quality assurance are paramount. It has a built-in data audit trail and gravimetrically controlled liquid handling. The Benchmate is primarily designed for tube-based applications and is not well suited for microplate applications.

One of the first generally accepted workstations for microplate-related applications was the Biomek 1000 from Beckman Coulter. It combined single and multiple channel pipetting, reagent addition and washing, and single-channel reading (densitometry). Other workstations are single- or multichannel (4-8) liquid handlers, often gantry type systems with one or two arms carrying canules or different tools (e.g., tube or microplate grippers), and 96- and 384-channel disposable or fixed tip pipettors. There are two notable exceptions to this architecture, the Biomek and the Benchmate (see above). The Biomek is different since it uses exchangeable tools, such as different pipettors, dispensers, and a gripper. It offers thereby a great flexibility with respect to different applications. The Biomek 2000 workstation misses, however, the ability to adapt to nonmicroplate formats and individual tip liquid level sensing on the multichannel tools.

As workstations are designed to provide a certain capacity to perform an application without operator attendance, i.e., walk-away time, they must have a minimal capacity for consumable storage on the working deck. Thus the footprint is always larger than needed for the liquid handling technology itself. In a robotic system there is no benefit to the large surface that most workstations have. In fact, for integration into a robotic system the large decks are nonproductive, since the robotic system already has a consumable storage capacity itself. Smaller liquid workstations retaining all required functionality, and being optimal for a robotic system because of a small footprint, have become available only recently. One of the best examples is the Presto Liquid Handler™ from Zymark.

Workstations such as the ones described here have proven to be extremely useful for combinatorial chemistry, compound weighing, dissolution and distribu tion, screening, and many other applications. They add in a significant way to the functionality offered by the stand-alone devices, albeit in a very different way. Many of the stand-alone devices are critical to working with microplates, while the workstations enable repetitive work, provide more consistent results, and may also allow the experimenter to do other work, i.e., they create walkaway time. As such, workstations have taken a prominent role in laboratory automation. With increasing plate densities (384-well plates and beyond) that are almost impossible to pipet to and from manually, workstations are no longer a luxury but have become a necessity. It is therefore to be expected that application of the new and smaller footprint workstations will rapidly extend and become a set of personal tools for the scientist.

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