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.

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.

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. 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 three-dimensional 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 said.


• Integrate with Molecular Devices’ microplate readers and AquaMax microplate washer
• Process batches of up to 50 microplates
• Walk-away automation
• Increased throughput

Molecular Devices

BioStack™ Twister® II

• Features a compact footprint and removable stacks
• Automates single or multiple instruments
• Features expandable capacity for up to 320 microplates
• Includes a rotational gripper for portrait and landscape carrier formats



• Accommodates SBS-approved plate types, including 96-, 384-, 1,536-, deepwell and automation-friendly PCR plates
• Features automatic reshuffle, with ability to sort and store plates in stackers for first-in, first-out (FIFO) processing
• Equipped for standalone operation or integration with other liquid handling devices



• Features an 8-second transfer time from stack to instrument
• Offers 2-, 4- or 6-rack options for a maximum of 360 standard microplates
• Delidding function removes and replaces microplate lids as necessary
• Able to integrate multiple instruments into a single benchtop system

Agilent Technologies