Automated pipetting is one of the most effective ways to minimize human error, increase precision and accuracy, and speed up a lab workflow. However, deciding on the “must-have” components for successful workflow automation liquid handling depends on your goals and applications. This article discusses some of the key points to consider when choosing a liquid handling platform for your laboratory.
Automating pipetting is a key step in improving laboratory workflows, helping to increase reproducibility, boost throughput, and reduce errors. Laboratories depend on automated liquid handling technologies for a diverse range of applications, including sample preparation, DNA extraction, cell-based assays, and ELISAs. These platforms are a long-term investment and should be selected based not only on today’s demands, but also the potential future needs of the lab. This will ensure that the correct platform is chosen, and can effectively serve the laboratory for many years to come.
First steps
Before making any decisions, take a good look at the processes to be automated:
Are you starting with a robust process?
Liquid handling automation can greatly improve a manual workflow, but it cannot fix an assay that does not already work. Break your workflow down into individual steps, and think about the potential impact of each one on the overall workflow. For example, taking an assay from a manually pipetted, tube-based format to an automated, higher-density, plate-based workflow means that the samples and reagents will be on the deck for a much longer period of time. How might this affect the integrity of your samples and reagents?
How will your needs change?
To save money, it might be tempting to invest in a system that only meets your lab’s current needs, but in the longer term you could lose out. Consider which elements are essential, and which would be nice to have. A good automated liquid handling system should be reconfigurable so that you can take on new applications and workflows as needs change. With a flexible, modular system, many elements of your current workflows can be repurposed and upgraded.
Is there an off-the-shelf solution that meets your needs?
Some specialized workstations have been optimized for specific applications with proven protocols, such as DNA extraction, sample preparation, and cell culture. This could vastly simplify your selection process, and still provide a useful “core” component to integrate into a larger system in the future. Off-the-shelf solutions designed with future integration and flexibility in mind are preferable to inflexible, “closed” platforms.
How much space do you have, and are you using it efficiently?
Space is often a precious commodity. Most liquid handling systems are now multiuser, which has increased the demand for flexibility and innovative use of space. Consider choosing an automated platform that can access space below the worktable to reach, for example, additional analytical or sample preparation devices, etc.
How easy is it to maintain and service?
Don’t overlook servicing and maintenance. Ease of access by technicians can reduce downtime and disruptions to your workflow.
Choosing the right hardware
Whether you are working in genomics, cell biology, drug discovery, molecular diagnostics, or something completely different, the right liquid handling system can make your life a lot easier. Important considerations include:
Air or liquid displacement pipetting?
Air displacement is ideal for dispensing over a large volume range, from 0.5 to 1,000 μL. Although only compatible with disposable tips, this increases speed and productivity by eliminating the extra steps associated with liquid displacement pipetting when changing liquids or flushing the system. It also reduces the risk of cross-contamination and provides a safe way to handle radioactive or biohazardous materials.
Liquid displacement is compatible with both fixed and disposable tips, and is the preferred technology for multidispensing volumes of less than 5 μL. Washable fixed steel tips are ideal for applications where tubes need to be pierced or positive pressure pipetting is required. For maximum flexibility, consider a system that includes both air and liquid displacement.
What volumes and formats do you work with?
Make sure the platform can handle the necessary pipetting volumes and labware formats (tubes and plates) commonly used in your lab. Also consider whether automation will allow smaller sample and reagent volumes to be used, offering potential cost savings.
Which pipetting arms should you choose?
The main types are 1) variable channel pipettes—generally 1- to 8-channel—that can handle tubes, plates, and many other labware formats; and 2) multichannel arms designed specifically for dispensing into multiple-well plates. Modern systems allow pipetting heads or adapter plates to be changed “on the fly”—a wise choice for protocols that use many different accessories, such as fixed needles, disposable tips, low-volume pin tools, etc.
Do you need robotic arms for extra flexibility?
Robotic gripper arms provide maximum flexibility by moving labware around the work deck. Robotic arms that can switch their “fingers” quickly ensure maximum flexibility and a secure grip for both tubes and plates.
Which type of pipette tip will maximize reproducibility?
Tip quality is a key contributor to reproducibility and can make or break system performance. Disposable tips are often perceived as the best choice to eliminate cross-contamination between biological samples. Some vendors also now offer special low-volume tips validated for reliable dispensing at the microliter or submicroliter levels needed for applications such as assay miniaturization. Consider purchasing the automation vendor’s own brand of pipette tips to ensure you get the most reliable results.
Instruments using fixed tips may have advantages with respect to operational cost. Fixed steel needles can often reach the bottom of deep vessels better than disposable tips, and can also pierce septa. Optimally designed tip wash stations reduce the risk of cross-contamination with this setup.
Do you need tips that are guaranteed sterile?
To minimize the risk of contamination, only use consumables that are labeled “sterile.” These are manufactured under stringent conditions and conform to packaging and transport standards that ensure tip sterility all the way to the lab bench. Products labeled “presterile” are sterile when they leave the manufacturer, but encounter many opportunities for contamination later.
Software matters
Software provides the interface with the person setting up and operating the instrumentation, and its design will determine how easy it is to program and interact with the system to configure workflows, set process parameters, and make data handling choices. It also has a direct bearing on how much training is required to operate the system confidently. Unless you have a software technician in-house, poorly designed software, no matter how powerful, can leave you dependent on the vendor or an external specialist to develop tailored protocols, troubleshoot problems, and make even the simplest programming changes. In many labs, the system operator is not a programming expert, and most IT teams will not get directly involved with instrument control software. As a result, you may have to wait for external consultants to be available, seriously impeding productivity and putting project timelines at risk.
Points to consider
Key questions to ask when evaluating liquid handling system software include:
- Can operators interact with a touchscreen for daily operation?
- Does the vendor have a library of existing protocols to simplify programming?
- What are the software integration capabilities for third-party devices?
- What is the extent of the device driver library offered by the vendor?
- Is the vendor experienced with LIMS interfacing?
- Would you be comfortable programming the system yourself?
- How easy is it for operators to set up their runs without programming expertise?
- What features—such as customizable graphical loading guides—do you need, and are they available?
- Is it easy to reconfigure the software when the system is repurposed?
- Can the vendor help to ensure cybersecurity?
Sample traceability
Full sample traceability can be essential for compliance with quality standards and guidelines. Barcode labeling, together with appropriate software, will simplify the tracking of both samples and consumables, and can prevent a loss of traceability. Automated labeling and tracking solutions can also:
- Indicate the location of labware on the deck and in storage units
- Ensure that barcode labels are properly applied and can be read correctly
- Accelerate barcode reading and sample picking processes, and streamline integration of middleware and LIMS.
The option to intervene
Mistakes are easily made, but not always so easy to fix. Many automation systems lack “start/stop” or “undo” functions, which may mean having to restart a program if you enter something incorrectly or need to pause a process. Look for a smart automation system that can detect, understand, report, and recover from an error, with start/stop functionality to allow safe and easy operator interaction with the work area of the instrument during a run.
Summary
Automated liquid handling can eliminate many tedious tasks, improving productivity and freeing up valuable time for more important work—but only if you implement the right solutions. Careful consideration of the points discussed in this article will help laboratories choose wisely, allowing them to reap the benefit of automated liquid handling and make life easier and more productive.
Post time: May-10-2022