#LabHacks: A little killer tool

Spatulas are used in kitchens to get fried eggs, burgers, fried vegetables or pancakes safely out of the pan and onto the plate. This great kitchen utensil also comes in handy in the laboratory – we’ll tell you how …

Tracy Dornblut puts on her lab coat and the orange safety gloves. She is on a mission to dispose of a toxic substance. Tracy is a technical assistant in the Protein Sample Production Facility (PSPF) at MDC. The proteins produced at the facility are largely used for research in structural biology.

The protein production process consists of several stages. The first stage is the cloning phase. Targeted segments of DNA are copied via polymerase chain reaction (PCR). Tracy or one of her colleagues then checks to see that it worked using a special method called agarose gel electrophoresis. The DNA is placed onto a gel and then separated by applying an electric field. “The DNA is negatively charged and moves to the positive pole; as it does so, the gel filters the fragments it contains like a sieve and separates them according to size. That’s how we can find out if the PCR worked,” explains Anja Schütz, head of the PSPF.

Of course, nobody in the lab team can see the tiny DNA molecules with the naked eye. That’s why the gel is stained with ethidium bromide, a dye that adheres to the DNA fragments. Under UV light, the fragments can easily be seen as they glow pink orange – almost the same color as Tracy’s gloved hands. She now picks up the spatula: “The ethidium bromide is toxic and has to be disposed of as hazardous waste. That’s why we don’t touch the gel with our hands but use the spatula to lift it out of the gel chamber and drop it into the special bin,” explains Tracy.

To make sure no one in the lab has the bright idea of using the spatula to fry up some eggs for lunch, it is marked with a skull – a real little killer tool.