Microtiter plates have become common labware in life science and medicine. Automated systems employing microplates in biological and chemical assays may consist of liquid dispensers, plate washers, mixers, readers, sealers, labelers, shakers, incubators and storage. Tying these components together are microplate handlers, which feature a computer-controlled robotic arm. Once programmed with a specific workflow, microplate handlers move microplates and deliver them to locations on various instruments precisely when they are needed.
Some handlers include built-in plate stackers. Those that do are usually limited to their original stacking and storage capacity. Users are able to add stacking units to systems without integrated stacking, as they would any other component.
Principal markets for microplate handlers are biology and medicine, but any industry that uses microtiter plates and requires a high degree of automation and reproducibility in assays will also benefit.
“Microplate handler” is a somewhat ambiguous term. Integrated microplate analyzers usually include some mechanism, which may or may not be recognized as robotic, for manipulating plates. True robotic systems are distinguished by their programmability and interoperability with any instrument within physical reach.
Microplate handlers evolved from bulky industrial robots that were programmed and adapted to hold microplates—a task for which they were clearly not designed. “They were overkill for the weight of a plate,” observes Todd Christian, who heads global marketing at Agilent in Palo Alto, Calif. Today’s handlers are designed specifically for laboratories and, with lab space at a premium, optimize the use of vertical space, thereby taking up less room on a benchtop. Pharmaceutical companies interested in eliminating human intervention in high-throughput drug screens were the earliest adopters. Soon biologists recognized that handlers permitted them to automate all aspects of any high-throughput experiment. Today robotics specifically designed for microplate handling are sold as either stand-alone instruments or bundled into a complete system.
Large laboratory equipment vendors may sell stand-alone robotic plate handlers, but most customers prefer purchasing the robotics already integrated with plate readers, stackers, and other instruments. For example, Agilent sells plate handlers by themselves but specializes in delivering complete workflow systems with user-specified components, some of which are sourced from third parties. Customers with dedicated automation groups may prefer to design their own systems from components they select, but they are the exception. “Our key strength is integrating components to meet a protocol or workflow that is unique to a customer,” Christian says. High on the list of specifications are plate capacity, incubators, and specific plate readers. Another is the ability to handle the gamut of microplate formats, up to 1,536-well format, and deep-well and low-profile plates.
Ease of use is a top priority with most purchasers of microplate handling systems. Robots must be “smart” about the space around them, particularly with respect to collision avoidance, and capable of rapidly “learning” precise endpoint positions in threedimensional space.
Most plate handlers must be “taught” key positions in space by manually moving the arm to the desired location and noting that in the control software. The path to the location does not matter—the robot automatically takes the shortest route. Maneuvering around objects requires creating and storing an intermediate location. Some advanced control software packages allow users to input set points in the software without actually moving the arm.
First-time users approach robotics with a combination of awe and suspicion. “They are especially nervous that the handler will drop the plate or improperly position it,” Christian notes.
Moreover, user requirements and expectations of automation differ widely. Many organizations, such as medical testing laboratories, purchase microplate handlers to carry out one or several specific tasks 24 hours a day.
Others, such as academic institutions, expect flexibility, versatility, and programmability, particularly for acquiring new plate readers or workflow changes. These users are better off investing in plate-handling capabilities based on anticipated needs; for example, rapid swapping in of components, particularly readers.
Understanding the customer’s workflow— the science behind the robotics— and being willing to source third-party instruments for specific microplate operations are traits that customers seek among vendors of microplate handlers.
“The ability to understand the experiment and to help customers select the right solution based on the right components is highly valued,” says Mary Duseau, VP of global sales for molecular medicine at PerkinElmer in Waltham, Mass. She adds that due to the complexity of microplate handling systems and the general lack of experience with robotics, purchasers of the systems require more “handholding” than do those who buy other instruments. “It’s important to serve both expert and novice customers,” Duseau told Lab Manager Magazine .
Angelo DePalma holds a Ph.D. in organic chemistry and has worked in the pharmaceutical industry. You can reach him at firstname.lastname@example.org.