How To Automate Your Lab, Part 3: Volume Ranges, Throughput, and Size

Determining how much liquid to move is key in finding a lab automation solution. Here's how to consider volume ranges, throughput, sterility, and size.

This post is an excerpt from our 18-page "Introducing Automation To Your Lab" e-book. Click here to download the e-book.

Chapter 4: How Much Liquid To Move?

To make lab life easier by automating liquid handling, a scientist needs to know how much liquid will be moved and how fast. That all depends on what workflows a lab runs and how quickly steps must be completed. One of the first features that scientists ask about a robot is: How much liquid can it move?

VOLUME RANGES

As mentioned previously, the liquid-handling sweet spot for most labs is 1–1,000 μl, which can accommodate a wide range of common life science workflows including sample preparation for polymerase chain reaction (PCR), library preparation for next-generation sequencing (NGS), nucleic acid purification, running ELISAs and more. Consequently, most life science lab managers will look for automated liquid handlers that excel in this range. As discussed in the previous chapter, pipetting sub-microliter volumes pushes up the price on a robot enormously. On the other end, pipetting higher volumes usually only happens outside of most research biology workflows and may not be a consideration for most labs.

LOW-, MEDIUM-, OR HIGH-THROUGHPUT?

Figure-5

In addition to the volume range that a robot can pipette, throughput—meaning, the number of samples you can process at once—is another crucial factor to consider. In many situations, the desire to increase throughput draws life scientists to automated liquid handling in the first place. When deciding which robot to use, you’ll want to consider whether you need low, medium, or high throughput.

For a lab that wants to move away from manual pipetting, but doesn’t run hundreds of samples a day, only low-level throughput—by the standards of automated liquid handling—is required. To get this amount of pipetting going faster, it just takes a robot that runs a single-channel pipette, or has limited multi-channel capability. Such a system can process a small number of samples, such as tens or hundreds a week, and can carry out most simple liquid-handling steps.

Scientists working with multiwell plates from 96 to 384 wells can find manual pipetting tedious at best and error-prone at worst. Here, a medium-throughput robot that works with an 8-channel pipetting head can serve the purpose. While there are robots that use 96- or 384-channel pipettes to do whole plates all at once, they are expensive. Increasing the number of channels obviously increases throughput, and can easily allow for the processing of hundreds or even thousands of samples per week.

For the highest throughput—such as that needed at a large pharmaceutical company screening tens of thousands of compounds or more—robotic liquid handlers can start to take up entire rooms of space, and consume a start-up’s entire bank account. But 90% of labs won’t need this capacity, so this concern is often moot.

Chapter 5: Space Considerations

One aspect that is sometimes left out of the lab automation purchase process is the type of space you need for your new robot. Automation platforms can have major requirements in terms of lab real estate, and giving up extra bench space can sometimes be the largest cost for bringing in a robot. You need to think about where the robot will fit, and what types of environment the robot itself creates.

STERILITY
In Lab Manager’s "2017 Automated Liquid Handling Survey Results" scientists selected “Safe sample handling - No cross-contamination” as the top feature on their shopping list, so a robot must not cross-contaminate samples. If it does, no amount of speed or convenience offsets that drawback. The good news is that this is a major consideration for anyone designing wet lab automation, and the robots on the market are much less likely to contaminate samples than a human operator. But exactly how sterile a robot keeps the samples on its deck is determined by the hardware included with that robot.

Some automated liquid handlers offer no protection between a sample and the wider surrounding environment, which can be fine for some situations. Other robots have simple glass or plastic barriers to prevent excess airflow across samples during a run, which is enough for many molecular biology workflows.

For those workflows requiring a greater degree of sterility, such as many tissue culture assays, fully enclosed systems with positive pressure and filtering can also be purchased. These platforms keep samples in what amounts to a tissue culture hood, including laminar flow, HEPA filtration, positive air pressure, and often ultraviolet lamps that keep contaminants out and/or destroy unwanted biology that get inside.

For labs handling dangerous reagents, keeping the liquid handler in a biosafety cabinet is the only viable way to keep both scientists and samples safe from contamination. That leads to another feature to consider—size. If a lab plans to keep samples contaminant-free by running a workflow inside a hood, then everything must fit inside that hood. So, in such cases, a robotic liquid handler and any associated equipment must fit inside the lab’s hood, and still leave enough room for access as needed. How small the robot has to be really depends on the size of a lab’s hood. In general, though, low- and medium-throughput systems are most likely to meet
this constraint.

SIZE
The footprint of the robot is a key consideration in other aspects as well. For example, if a researcher wants to be able to easily move the robot, it needs to be small enough to enable that. Even some medium-throughput systems are small enough and light enough for a two-person lift. Then, a platform of that size and weight can be moved to different spots, between labs, or even in and out of a hood if needed. That kind of robot is not only movable, but also more manageable in terms of bench space. Without taking up so much room, it’s easier to put a smaller robot where it’s needed, close to associated equipment for a specific workflow.

As a liquid handler gets bigger and more complicated, possibly including multiple arms and various accessories, it takes up more space—too much to sit on a bench. Sometimes, robots just need to be big and take up lots of floor space, but these systems are far from mobile. While they are the right tool for some big jobs, they are also far more than most labs would ever need.

This post is an excerpt from our 18-page "Introducing Automation To Your Lab" e-book. Click here to download the e-book.