Fun with lasers
Laser microdissection may sound made up, but it is a real technique used at the Noble Research Institute and it is as cool as it sounds. Microdissection is used when we want to examine the RNA or composition of a specific cell type that is difficult to separate normally. For example, it normally isn't possible to separate the vascular tissue of a small stem from the surrounding tissue, as it is often only a few cells in diameter. If you wanted to study the proteins that make up this tissue, you would be out of luck. However, with microdissection, it is actually possible to remove the tiny disks of vascular tissue from the rest of the plant.
Microdissection starts with the use of a cryostat microtome to slice the tissues into 15-micron-thick slices. The microtome is essentially a very fine deli slicer, cooled to extremely low temperatures. One the samples are sliced, they are placed onto a special cutting membrane and allowed to warm up, adhering them to the membrane. The membrane is then placed into the micro dissector, and then the magic happens. The sample is magnified and projected onto the screen and, using a mouse, a line is drawn where we want the laser to cut. The fire button is hit, and you can watch the laser blast through the tissue, separating it from the other tissue. Then, you press the harvest button and a tube slides over the sample, which is blasted up into the glue-covered-cap of the tube by a laser. You can queue up many cuts on a sample and walk away while the laser does its magic.
I'm very glad I got to use such an awesome piece of technology, and I'm sure that being trained on it will come in handy whenever I want to isolate small tissue samples. Plus, blasting things with a laser, even if it is tiny, is a ton of fun!
Michael Passalacqua is a 2016 Lloyd Noble Scholar in Plant Science from New York, New York. He is a rising senior at Rice University and is majoring in biological sciences with a focus on genetics. His summer research project is studying the pathway of a gene that, when inactivated, vastly increases the biomass of crops harvested multiple times.