The reign of the manual pipette
Ergonomics has revolutionized the way we all think about workstation design. Working with an understanding of ergonomics enables millions to work all day, every day without undue pain or strain. The success in adapting the computer workspace for ergonomic considerations has been, to date, unmatched in the research laboratory. There are several unique challenges in adapting biological research workflows to ergonomic solutions unlike a computer workstation. These includes infrastructure designs which are based on safety requirements, highly variable working environments, as well as experimental limitations to adapting procedures. Where ergonomics is the science of adapting the workplace to the job, often in scientific research, the job is adapted to the science to be done. And that job has been changing in recent years.
Over the past 20 years, there has been a large shift in what type of research is most common. Once a niche subject, Molecular Biology and its study of genes, proteins and individual cells has been incorporated into most other disciplines such as biochemistry, cell biology, microbiology, medical diagnostic testing and especially drug development. This has influenced both the course of drug development and the nature of work being done by professionals in the Sciences and Engineering fields. The manual pipette (Figure 1A) now reigns supreme in the lab, and is used for the vast majority of tests and experiments today. The manual pipette enables scientists to move, mix, and aliquot not only large but also extremely small volumes of liquid samples with extremely high precision. Unfortunately, manual liquid handling raises some serious ergonomic red flags, and the number of hours per year drastically increasing the number of users who report pain while pipetting (1, 2). Ergonomic pipetting solutions are required for manual liquid handling methods since the process raises issues in terms of repetition, force and posture (2).
Several research studies have been conducted on the risk for repetitive strain injuries faced by laboratory operators, and the information paints a stark picture.
With only 2 hours of pipetting activities per day, the average time spent in the field, a technician or biologist already faces drastically increased risk of repetitive strain injuries. However, workplace surveys find that pipetting activities can take up to 88% of the workday for certain staff (3). Using a standard work week as a guide, this puts current estimates of pipetting activities between 1,200 and 1,900 hours per year, which largely exceeds (by 4 to 6 times) the identified limit for increased risk of workplace injury. In the United States, lost productive time as a result of repetitive strain disorders is estimated at 61 billion dollars, and a workplace repetitive strain injury can result in up to 185 days of missed work per year (4, 5). While these statistics paint a worst case scenario picture, even technicians who have not yet experienced debilitating pain often alter their pipetting technique with compensatory moves to avoid pain, thus decreasing the accuracy of their work and wasting valuable resources and samples.
Repetitive strain injuries, a frequent problem of pipette users
Most commonly used manual pipettes are handheld, operated primarily using force applied by the thumb in an extremely repetitive fashion. Indeed, one standard pipetting cycle typically includes 6 steps (Figure 2), which according to NIH studies, are carried out between 6,000 and 12,000 times a day for an average pipette user in the United States (6). Mixing by pipetting is also a common addition to this protocol which involves vigorously depressing and releasing the plunger with the thumb. Each single mixing step encompasses 60 to 90 repetitive movements per minute. In addition to being highly repetitive, the force required to depress and release the plunger with the thumb is often much higher than what is recommended for safe working conditions. The standard calculation notes that for each dynamic movement the force required should be less than 30% of the maximum strength capacity.
This limits force applied in each movement of the thumb to 3 and 2.1 kg of force for men and women respectively (6). While some of the steps involved in pipetting are under this limit, depending on the pipette and method used, half of the movements requiring force applied by the thumb are over it (Figure 2). In particular, depending on the method of inserting a disposable tip onto the end of the pipette, the forces involved in tip attachment and ejection can require up to 475% of the recommended maximum limit (1). With thousands of replications per day and forces which can drastically exceed the recommended limits, the risk for repetitive strain disorders for research scientists and technicians cannot be overstated.
Even when using the most modern pipettes with soft plungers and ergonomically designed handles, the main problem of repetition is not fully eliminated.
Body posture during pipetting: another source of workplace injuries
Technicians and scientists pipette to precisely move and combine liquids of very small volumes. To accomplish this precision, proper pipetting technique is essential to achieve the performances indicated by the ISO norm 8655. This generally requires the arm to be held elevated and extended away from the body for long periods of time. The pipette must also be held vertically, which requires rotation and hyperextension of the wrist and thumb. Any alteration of this posture can lead to a significant reduction on the accuracy and precision of the pipetting process. The pipette must also be lifted higher at several steps to accommodate the dimensions of tips and consumables, as well as bins for disposal of contaminated tips. While dispensing samples into destination tubes, high precision and concentration is required and many users adopt awkward positions with their neck and head to allow precise manipulation of the pipette tip into small wells. In addition, many protocols involve dangerous chemicals or high risk biological samples, often requiring research scientists to pipette inside fume hoods or biosafety cabinets and while wearing uncomfortable protective clothing and gloves, which add stress to users and force them to adopt even more awkward and extended postures (Figure 3)
Approaches to improve ergonomics in the research lab
Ergonomic solutions to address pipetting workflows ideally would address all the issues raised by repetition, force, posture and duration. Common recommendations for improving the ergonomics of a workstation include changing the workstation heights (desk, monitors or keyboards being common examples), adjusting posture, rotating tasks and taking breaks. While these solutions are effective in environments where they can be easily introduced, such as offices, they are often not suitable nor cost effective for a laboratory (Table 1). There are several solutions available to effectively address individual steps in the pipetting workflow (Figure 2), but none of them tackle all the areas of concern simultaneously.
One solution introduced with good effect is cappers and decappers, used upstream of the pipetting workflow. These reduce the number of pinching, gripping and twisting movements required during a day to take off and put on lids. Another solution is ergonomic pipettes that require reduced forces for accurate plunger depression, and several also incorporate a more neutral arm position. These improvements do address several concerns with pipettes; however, a user survey of several manufacturers found that even when these ergonomic features are improved, there is often a tradeoff between speed and ease of use for experienced users (6). Ergonomically designed pipetting workbenches have been designed by different manufacturers, but the design is so far from what is currently in place that they require a complete overhaul of the infrastructure of research labs, and are not applicable to biosafety cabinets or fume hoods. There is a real need for costeffective solutions which require minimal adaptation of the current infrastructure, address fume hoods and safety cabinets, and can also be positively embraced by technicians and scientists and easily incorporated to their daily work.
Andrew: a solution for a start-to-finish ergonomic pipetting workflow
At Andrew Alliance, we have introduced Andrew – the best au- tomated liquid handling solution to the ergonomic challenges posed by the pipetting workflow with single channel pipettes (Figure 1B). The Andrew suite of robotic pipetting solutions are vision assisted, anthropomorphic robots for automated liquid handling. The uniqueness of Andrew resides in its design, which is conceived to allow the use of the most commonly found and commercially available pipettes (Gilson and Rainin) and consu- mables. Handling these pipettes just like a human operator would, Andrew can grab and change pipettes, set and change the volume, insert and eject tips, aspirate, mix, and dispense liquids, all in an extremely accurate and reproducible manner.
Furthermore, Andrew can conveniently function inside standard fume hoods and biosafety cabinets, removing from the user the pain of adopting the uncomfortable and risky postures normally required for performing manual pipetting inside them.
The easy-to-use software requires minimal training and enables all lab members to design and program pipetting protocols for execution by Andrew.
These protocols allow walk-away, fully automated pipetting procedures from beginning to end, com- pletely liberating users from repetitive strains on their hands and shoulders. With this all-in-one solution, laboratories are no longer required to adjust the lab infrastructure, replace all the manual pipettes, hire additional technicians to enable task rota- tion, and solve the problem of working in fume hoods and safety cabinets. By reducing the risk of repetitive strain injuries for technicians and scientists, Andrew keeps them happy, healthy and productively focused on what really matters: Science.