Automated liquid handlers encompass a range of instruments and systems whose function is to dispense liquids rapidly, usually in very small quantities, at user-specified volumes, and with great accuracy, precision, and reproducibility.
As the successors to manual pipettes, automated liquid handlers are the principal enablers of rapid experiments and assays conducted in tubes, vials, or microtiter plates. Liquid handlers are often just one component of systems consisting of microplate handlers, washers, readers, stackers, shakers, and incubators.
Automation became necessary as assays were miniaturized from vials to tubes, and finally to microplates, and as researchers switched from radionuclide-based assays to tests that used nonradioactive detection.
Biology, medical testing, and screening of development-stage drugs are the primary markets for automated liquid handling. The energy, environmental, and heavy industries also use liquid handlers when accuracy and reproducibility, but not necessarily high throughput, are desired. “Any time you work with many samples and small quantities of fluids, automating liquid handling with a workstation will provide good return on investment,” says Scott Eaton, director of robotics marketing at Hamilton (Reno, NV).
Another factor to consider, Eaton says, is the effect of physical forces on very small liquid-dispensing volumes used in higher density plates. “While 96-well plates remain the most common, 384- and even 1,586- well systems that employ sub-microliter volumes are gaining in popularity. At these volumes, evaporation and absorption onto the plastic plate surface become issues.”
Automated liquid handlers have evolved from automated pipetting systems to workstations that employ liquid handling as one component, according to Nance Hall, vice president for automation and detection systems at PerkinElmer (Waltham, MA). Today’s systems perform washing, incubation, and plate manipulation in addition to dispensing. “In the past, liquid handlers performed just one function; today, they are ‘application solutions’ in which liquid handling is part of a larger picture,” Hall says.
Hall suggests that potential buyers analyze their liquid-handling needs the way a cook examines a recipe. “What are the ‘ingredients’? What labware are we dispensing from and into? What volumes are involved, and what sample-tip options are available?” Hall says. “Users who fail to optimize the liquid handler’s fluidics design to desired volumes will be forced to compromise either on performance or throughput.”
Liquid handling is just one component of what may be a complex workflow, according to Jason Greene, liquid handling product manager at BioTek (Winooski, VT). “Operating manually, users must work through the various reagent additions, incubations, washing, and reading steps,” he says. “Nobody likes to wash microplates. It’s pretty easy to get users to buy into the idea of automation on that function alone.”
• Feature up to 16 independent pipetting channels as well as 96 or 384 multi-channel heads
• Autoload option provides barcode tracking of samples, labware, racks and carriers
• Pipetting channels and labware grippers move independently of each other, supporting a wide range of labware
•Based on air displacement pipetting technology
Freedom EVO Series
• Liquid volumes range from 100 nl to 5ml and can be extended with DynamicFill™ Technology to 50 ml and higher
• Pressure Monitored Pipetting (PMP™) detects errors by comparing recorded and realtime-simulated pipetting pressure signals
• Liquid handling arm can be equipped with disposable tips and/or washable tips
• Easily manages and processes 96 blood tubes with an innovative rack system
• Uses on-deck sensors and integrated bar code reader to identify and track samples
• Features non-contact liquid level and clog detection
• Pipetting approach eliminates the need for electrostatic tips
Caliper Life Sciences
CO-RE 384 Shifted Tip Pickup (STP)
• Picks up one column, one row or one tip without changing heads
• Ideal for performing serial dilutions in 384- and 1,536-well plates
• Employs CO-RE (Compressed O-Ring Expansion) technology and air-displacement pipetting
•When used with Rocket Tips, the need for a second head and arm is eliminated/p>