Lab Tools: The History of the Pipette

By Erin Biba

Any scientist that has ever worked with liquids will likely say the pipette is one of the most essential tools in the lab.

Unless you work in a lab, it's possible that you've never seen a pipette in person and only have a vague idea about what it does. But any scientist that has ever worked with liquids will likely say the pipette is one of the most essential tools in the lab. Modern versions of the tool require just a press of a button to pick up a specific volume of liquid and move it. It's a bit like an eyedropper, but with the ability to control specifically how much liquid you are picking up and dispensing. The pipette is most commonly used in genetic research, chemistry, microbiology, and drug development.

Photo credit: Flickr user gemmerich via Creative Commons

In what is probably the most horrifying revelation in all of these lab tool histories so far, the reality about life before formal pipetting is that when scientists didn't have proper tools to move liquids around they just used a straw and their own mouths to create suction. According to a paper titled "Hazards of Mouth Pipetting," produced by the US Army Biological Laboratories in 1966, one of the earliest recorded examples of the hazards of using one's mouth for this purpose came in 1893 when a doctor accidentally sucked a bunch of Typhoid bacteria into his mouth. The paper went on to express concern that it was much too easy to inhale vapors, especially from radioactive solutions, even when the liquid being transferred never made contact with a scientist's mouth.

It's remarkable, given the history of pipettes, that the "mouth pipetting" method managed to continue into the 60s. According to the US Army paper: "the method of avoiding pipetting hazards is so elementary, so simple, and so well-recognized that it seems redundant to mention it." But, nonetheless, the paper goes on to say that only a few institutions at the time had issued rules that forbade scientists from using their mouths to move infectious and toxic materials around their labs. In fact, Manhattan Project scientist Lawrence Bartell accidentally ingested plutonium using this method -- luckily he lived to tell the tale.

Credit: Sarah Harrop, Medical Research Council

Scientists certainly had the tools available to them at that time. The earliest pipettes were invented by Louis Pasteur, one of the scientists responsible for proving the validity of germ theory. For a few hundred years before Pasteur came around science had suspected the existence of microorganisms, but had never been able to prove their existence. Pasteur managed to show that microbes were responsible for food going bad by closely studying the fermentation of milk and wine. The result of this research was twofold. First, of course, was his most famous achievement: developing the method of pasteurization, which uses heat to remove bacteria from food. The second was the creation of rudimentary pipettes, know today as the Pasteur Pipette, which he deemed essential to prevent liquids from becoming contaminated when they were moved from place to place in his lab. The new method used thin glass tubes with a rubber bulb at the end, which created suction. Pasteur Pipettes don't have the measuring sophistication that modern pipettes have, but they are still in use today (now also called "transfer pipettes" they're usually made of one single piece of plastic).

It wasn't until the late 1950s that the pipette began to get its modern-day makeover. According to a paper by researcher Martin Klingenberg, who worked closely with the modern pipette's inventor Heinrich Schnitger, at the time scientists that wanted their pipettes to measure specific volumes of liquid had to create their own personal set. They were "made by heating a glass tube over a Bunsen burner and tugging at one end to create a capillary. Further heating a few millimetres from the tip of the capillary created a restriction that allowed air flow, but limited the flow of liquid to define the volume. The pipettes had to be calibrated gravimetrically with mercury or using a dye. Pipetting itself involved sucking the fluid by mouth up to the restriction—not surprisingly, precise pipetting required experience, and depended on the user and pipette construction," he wrote.

According to Klingenberg, his colleague Schnitger, a former German soldier who contracted tuberculosis during WWII and began studying medicine "to control his health while protecting himself from incompetent doctors," was regularly annoyed with how cumbersome pipetting technology was. And, said Klingenberg, "Schnitger viewed micropipetting by mouth with great contempt." Overcome with frustration while working at the University of Marburg, it took Schnitger just two days to build the first micropipette, called the Marburg Pipette. The new device was capable of measuring liquids down to the microlitre and had a spring and piston on one end that created suction. After a few upgrades his design was eventually licensed and mass-manufactured by medical supply company Eppendorf.

credit: Brookhaven National Laboratory

Since then the pipette has gone through a whole series of upgrades and modifications to perfect its design. In the late 1970s, Warren Gilson and Henry Lardy (who some controversially claim were the true originators of the micropipette) made the first version of the device that was adjustable and could be changed to measure different volumes of material. In 2007, physicists at Brookhaven National Laboratory invented a pipette that can dispense a zeptoliter of material (that's a billionth of a trillionth of a liter). And, of course, many of today's pipettes are controlled by robots. But despite all these high tech advances you can be sure there are still scientists out there using glass tubes and their mouths to move liquids around their labs when no one is looking.