Addressing the Ergonomics of Pipetting by Hand
Pipetting, the transfer of liquids between different types of equipment, is a daily occurrence in the lab. Traditionally this has been performed using handheld pipettes and, given the often-varied form factors of the lab equipment involved (e.g. test tubes, sample tubes, and multi-well plates), this can mandate the use of a single-channel pipette capable of transferring only one sample at a time. As such, pipetting can be a repetitious and time-consuming process and there is considerable value in improving on the traditional single-channel model.
In seeking to reduce the repetition and strain involved in a task such as pipetting, along with the resultant risk of repetitive strain injury (RSI), several questions concerning the ergonomics of the process must be addressed: How can the number of repetitions be reduced; How can the number of actions within each repetition be reduced; and, for those actions that cannot be eliminated, how can the effort required be minimized?
Reducing Repetition and Complexity: Multi-Channel Electronic Pipetting
The repetitive motions required by a manual, single-channel pipette can now be quickly and efficiently performed using electronic pipettes. These devices feature a multi-dispensing mode that enables aspiration of a larger liquid volume followed by repeated dispensing of several smaller volumes. Combined with a multi-channel pipette tip array, this allows the transfer of multiple samples in only one action.
Notably, for multi-channel pipetting to be successful, the form factor of the relevant lab equipment must be considered, and the pipette must be flexible enough to cope with the variation encountered. One such example is the Thermo Scientific™ E1-ClipTip™ Electronic Equalizer Multichannel Pipette, which uses the E1-ClipTip™ system. Here, the adjustable tip spacing feature allows you to set the distance between pipette tips for different types of labware by simply sliding a handle, while the interlocking tip interface ensures that pipette tips are securely locked and sealed on the pipette to avoid uneven loading.
Thermo Fisher Scientific has compared the performance of this system to a single channel, manual pipette in terms of the time required to transfer liquids. For example, the transfer of samples from eight microcentrifuge tubes to a 96-well microplate is reported to take 90 percent less time using an eight-channel pipette than performing the task manually.1
"[…]multichannel electronic pipettes will take up to 90% less time and reduce 90% of tiresome repetitions compared to single channel pipettes.”
A notable part of this time saving comes from the reduction in the number of motions required to perform each action. When using an electronic, multi-dispensing pipette such as the E1-ClipTip™; Electronic Equalizer Multichannel Pipette, the repetition of forearm movements can be substantially reduced, while thumb movements are reduced by index finger trigger operation and electronic tip ejection. As a result, pipetting becomes more efficient and the risk of RSI is reduced. To assess the benefit of the Equalizer pipette system, the number of forearm and finger motions were counted in the same 96-well microplate filling test. The Company reports that using the ClipTip™ system results in over a 90 percent reduction in actions compared to a manual pipette.1
Reducing Effort: Tip Attachment and Ejection Forces
Reducing the force needed to attach and eject tips plays a crucial part in good pipetting practice, as it supports better accuracy and precision, and helps to avoid the risk of RSI. Tip attachment and ejection forces vary significantly among different adjustable tip spacing pipette brands and, while many brands claim their devices require the lowest force, data is often lacking. In examining the E1-ClipTip™ system, Thermo Fisher Scientific™ compared minimum force requirements with those of two other eight-channel, adjustable tip spacing pipettes (Manufacturers A and B).2 Tests were performed 10 times in a standardized way and pipette tips were of the type and attached by the method recommended by each manufacturer. Measurements were averaged and standard deviations from mean were calculated.
The E1-ClipTip™ Equalizer Pipette has up to 87 percent lower tip attachment and up to 93 percent lower tip ejection forces compared to other adjustable tip spacing pipettes.
Tip attachment forces for the E1-ClipTip™ Equalizer Pipette were up to 87 percent lower compared to the other adjustable tip spacing pipettes tested, while tip ejection forces were up to 93 percent lower.2 These ejection forces are minimal due to an electronic ejection function, triggered by pushing an ejection key, a function which aids ease of use considerably.
Summary
The use of electronic, multi-dispensing pipettes fitted with a multi-channel kit can dramatically reduce the repetition, mechanical complexity, and effort involved in liquid transfer. This reduction in time of operation and effort required all improve the efficiency of the process and limit the ergonomic ‘cost’ of pipetting, reducing the risk of both RSI and procedural errors.
References
1. Is there an easier and more efficient way to transfer liquids between various labware formats, than using traditional handheld pipettes? (Smart Notes, Thermo Fisher Scientific, COL07763 0918)
2. Select adjustable tip spacing pipettes with the lowest tip attachment and ejection forces (Smart Notes, Thermo Fisher Scientific, COL011613 0320)
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