STANDING THE TEST OF TIME
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 indispensable 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 From a tool originally made to measure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
- 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
- Martin, J. A. (2001) The Art of the Pipet, BioMedNet Issue 100
