What to Consider Before Buying a Liquid-Handling Solution

Most, if not all, life science labs need to accurately transfer liquids, which usually involves some kind of pipette or liquid dispenser. This article explores the key issues to consider when selecting a liquid-handling approach.

“There are a variety of liquid-handling options, from simple pipettes to liquid dispensers,” says Annemarie DeCharles, Director of Product and Portfolio Management, Liquid-Handling Solutions at Thermo Fisher Scientific. “It can be confusing to sift through all the information and material.” As she points out, “There are a variety of pipettes currently on the market, ranging from fixed-volume, single-channel, manual, or electronic pipettes.”

Before jumping into the specifics about pipettes, Lukas Keller, Director of Marketing and Communications at INTEGRA Biosciences, suggests a few general things to consider:

• What are the physical properties of your liquid?
• What volumes will be transferred?
• What throughput will be required?
• What vessels will you be using?

The answers to these questions will help a lab manager select the best liquid-handling solution.

Handheld options

For any handheld pipette, a variety of features can make all the difference between accurate liquid transfer and agonizing inaccuracy. Some of the key must-have features, according to Keller, are:

• A light and well-balanced pipette
• A grip design that fits comfortably in your hand
• Low tip-loading and ejection forces

Then, there’s the increasingly asked question: manual or electric?

DeCharles notes the advantages of a manual pipette:

• It enables broad usage to fit any workflow
• Often easy to calibrate
• Best for low-throughput workflows

For the downsides of a manual pipette, DeCharles points out that “the accuracy and precision of pipetting is highly dependent on the user, so good pipetting technique is critical.”

For advantages of an electronic pipette, DeCharles states:

• The user isn’t required to manually move the plunger during pipetting, so these instruments are more ergonomic—requiring, fewer hand movements
• The piston movement in electronic pipettes is independent of the person pipetting, which minimizes the user-related challenges with accuracy and precision
• Electronic pipettes are also better suited for long pipetting series, and offer more reproducible results, as they are less prone to human error.

For higher throughput or replicates, a handheld pipette might not be the solution.

Adding automation

Today’s workflows are longer and more involved than ever before. They also involve lower volumes, where the quality of liquid transfer is an absolute key to success.

When asked about the key things to consider when purchasing a liquid-handling solution, Kay Chang, Product Manager of Liquid Handling at Blue-Ray Biotech, gives a list of basic specifications:

• Throughput
• Accuracy and precision
• Volume range
• Channel number
• Labware compatibility

Some applications might require more advanced features. “For example, a temperature-control device will be needed to operate temperature-sensitive samples or reagents, a disinfection module will be required to operate microbial experiments, etc,” Chang says.

Image. For liquid handling, scientists can consider many options. Image courtesy of Hamilton Company.

Going over these features should help a scientist focus on what a lab needs in liquid handling, but it’s important to understand them in the context of a lab’s specific application. Before diving into automated liquid-handler features, says Kevin Miller, Senior Market Segment Leader and Scientific Content Manager at Hamilton Company, “Labs should first start with their goals: What do they want to achieve?” This understanding is crucial to guide the selection process, and Miller says that it goes beyond the obvious requirements for high accuracy and precision. As he says, “Understanding the goals both today and tomorrow helps to finetune a system with integrated tools, and also facilitates scalability and change as the lab evolves.” In addition, Miller encourages scientists to depend on the automation manufacturer’s experts to help them navigate the many options out there to find a system that’s optimal for their needs.

When those questions can be answered, it’s time to shop for a liquid handler.

Select the right size

The size of a liquid handler—what it can really do—might be the key decision. It must be at least big enough, and maybe a bit more.

“You really want to make sure that you get a system that fits your application,” says Mike Asham, director of applications sciences and solutions at Opentrons Labworks. “Start looking not only into what you are doing now, but what you want to be doing two years down the road.” As an example, he notes, “Make sure that there’s enough real estate on the deck, as well as forward-looking features to meet the requirements of your application.”

Nonetheless, every lab doesn’t need a gigantic liquid handler. In next-generation sequencing (NGS) workflows, for example, some liquid handlers can run multi-well plates through the process faster than a lab can analyze the data. This is why understanding the goals is so important, Miller says. “NGS is tip-intensive, so you need adequate deck space to accommodate all of the tip racks, but increasing throughput with a very large, automated liquid handler can create a bottleneck in analysis that doesn’t help the lab to improve efficiency,” he says.

So, the right liquid handler balances a lab’s needs with its capabilities.

Ease of use

In a liquid handler, software controls what the device does, and someone needs to create or customize that software. “Again, this goes back to the goals: To what extent do you want to program?” Miller asks. Some liquid handlers are pre-scripted with protocols for specific assay chemistries, and users can tweak these protocols as desired. Users with advanced programming experience can create custom protocols. Miller recommends entrusting experts from the automated liquid handler’s manufacturer for programming guidance that gets users up and running quickly.

Image. Some facilities, such as the Liverpool Airport shown here, set up dedicated laboratories that include liquid-handling platforms. Image courtesy of Bio Molecular Systems

The hardware also impacts how easy a liquid handler is to use. Here, Mike Slinger, Sales Manager-UK for Bio Molecular Systems, encourages users to find a fully open system. That’s one that’s “not tying the user into using specific laboratory plasticware, such as sample tubes and PCR plates,” he says.

When a liquid handler provides the right blend of software and hardware for a lab’s needs, a user gets the most options. “Make sure that it’s a customizable platform—many robotic systems are not,” Asham says. “The flexibility allows you to adapt the platform to your future needs.”

A discussion of pipetting of any sort is incomplete without mentioning cost. Here, scientists should demand certainty. “Ensure that the system is priced to include all of the accessories required for a specific workflow,” says Slinger.

All along the way to a pipetting purchase, asking questions within a lab and among vendors can make the difference between buying something great or something disappointing.