Standing the test of time

Laboratory News is not the only one celebrating 40 years; this year Gilson marks 40 years of another lab favourite. Peter Tudor takes a look back at how things have changed. 

Just as a paintbrush is to an artist, a pen is to a writer and a scalpel is to a surgeon, the pipette is a laboratory technician’s best friend; an indispensible part of the modern lab. So much so, that some users hang on to their equipment for as long as possible.

The history of the pipette, and its use as an instrumental tool in medical research and the development of science as a whole can be traced back to the eighteenth century. French chemist, Francois Descroizilles designed a tool called a burette, which was amongst the first apparatus to accurately measure and dispense liquids.

It wasn’t until 1969 that Dr Warren Gilson invented the world’s first adjustable volume pipette – Pipetman – which continues to be manufactured in France in a factory started by his colleague and manufacturing mentor, Eric Marteau D’Autry. Having designed a device in the 1940s to measure respiratory volumes in a circular format with a digital readout, Gilson combined this with the features and the engineering of a German-made pipette to invent a pipette with a digital readout and counter wheels. It was compact and cheap to make. Importantly, it dispensed accurate volumes of liquid. British scientists were first introduced to Pipetman in 1971 and in 1972 the Pipetman Classic was launched.

The modern day air displacement pipette was developed by Warren Gilson and Henry Lardy from a device used to measure the amount of oxygen used when cells grow. This machine included a tool to measure air pressure utilising a tiny piston to gauge changes in the amount of oxygen. They discovered that moving the piston into a small pipe would push air out, and moving the piston in the other direction would suck water up. From a tool originally made to measure the change in tiny amounts of air, the inventors set out to make a tool to measure and move tiny amounts of liquids.

The past 40 years have been pivotal in the development of the pipette, as we have come to know it today. A recent study revealed that 57-88% of a scientist’s time in the laboratory involved the use of pipettes, which is a considerable amount of the working day!

The look and feel of pipettes has changed subtly, for example Gilson and Marteau D’Autry phased out the original volume adjustment assembly, once found on the handle. In response to the AIDS epidemic in the 1980s, the rotary drive system was modified to make it easier to adjust the volume with gloved hands. Marteau D’Autry introduced the steel tip ejector in 1991 and then, in 1995, there was the arrival of the top adjuster knob.

As ergonomics have developed to reduce the risk of repetitive strain injuries, pipettes have since become a lot more comfortable to use. Components have been added to ensure that strains are reduced when pushing down on pipette plungers and depressing tips and the market has been awash with different solutions all designed to help the end user. Motorised electronic versions can now dramatically reduce hand pain related to prolonged pipetting.

An ergonomics study1 in a research lab determined the risk of Musculoskeletal Disorders (MSDs) from the use of pipettes and other common lab tools. Intense repetitive movements ranging from 59 to 89 per minute were maintained over prolonged periods. The use of pipettes requires a dexterity that is often complicated by tasks that force the operator to adopt awkward postures. Interestingly the study showed that the risk associated with an extended use of pipettes not only depended on the ergonomics of the pipettes, other lab devices and furniture, but also on factors such as an individual’s physical characteristics, work rhythm, postural constraints and environmental conditions.

Gilson has also shown that psychological factors generate physical stress. The pipette is a precision instrument. The more scientists trust their instruments and trust the performance of their pipette (being unconsciously accustomed to their pipetting methods), the less mechanical stress they will develop. Pipetman’s robustness and longevity has been a reference for many scientists who have developed their best skills and pipetting technique using a timeless trustworthy pipette. The modern day air displacement pipette, a design whereby an air pocket sits between the mechanical piston and the liquid being dispensed to avoid contamination, is an incredible tool of high precision, able to draw up 1.0uL of liquid with an accuracy of 3%2.

Pipettes have played a part in many applications over the years. The Microman, a positive displacement pipette (where the liquid is in direct contact with a disposable capillary tube and piston) invented by Gilson in the mid 80s, was arguably one of the most pivotal instruments in the development of forensic science, analytical studies in molecular biology and advances in the PCR (polymerase chain reaction) technique, which gave molecular biologists the ability to generate millions of copies of DNA from a single strand.

PCR has enabled major advances in the recognition, study and manipulation of the DNA sequence, which has had a monumental impact on science and medicine. For example, the technique has allowed medical researchers to identify hereditary diseases in humans; lab technicians are now able to readily clone DNA; and forensic scientists are able to use PCR techniques to map the human fingerprint.

Positive displacement pipettes are used extensively in food and drink, biotechnology, clinical, and industrial laboratories. The International Dairy Foundation, for example, recommends the use of a positive displacement pipettes to determine the lactose content in milk.

Programmable pipettes are now starting to emerge, connecting PCs to pipettes. Software allows users to create pipetting protocols on PCs and transfer them to pipettes. They offer a wider volume range, meaning that fewer models are required. There is improved accuracy and precision by eliminating operator-to-operator variability.

In the next 40 years, this icon of molecular biology will continue to help scientists deal with ever more complex samples. Its accuracy and precision will address the emerging needs of even smaller volumes. Recent developments in productivity have led to the development of multichannel versions of the micropipette and the trend remains to process even more samples. The micropipette will have to adapt and offer new solutions to increase productivity at the bench, whilst always guaranteeing the accuracy of the volumes dispensed. Liquid handling may eventually change altogether with the development of new technologies, such as lab-on-a-chip devices. However, from the initial Pipetman to the 21st century manual liquid handling needs, Gilson’s Pipetman remains at hand with the technology to offer yet more to help the busy scientist.

REFERENCES

1. K.R. Asundi, J.M. Bach, D.M. Rempel, “Thumb force and muscle loads are influenced by thedesign of a mechanical pipette and by pipetting tasks,” Hum Factors, 47(1):67–76, 2005
2. Martin, J. A. (2001) The Art of the Pipet, BioMedNet Issue 100