Those cool pictures from electron microscopes of fleas, bedbugs and other tiny creatures have one drawback: the animals die during the process, which means scientists miss out on imaging the bugs while they’re alive — and miss out on filming important biological functions. Tiny “space suits” might be the answer.
Electron microscopes make images by beaming electrons at the subject matter. The problem is that it has to be done in a vacuum chamber, which means any living thing critter isn’t going to stay that way. Samples for a scanning electron microscope have to be specially prepared — even the water in a small creature’s body will evaporate, causing it to collapse.
But a team of Japanese researchers used a new a approach. They coated specimens in a non-toxic detergent called Tween 20. When they put the coated organisms in the vacuum and hit them with an electron beam, the detergent formed a lattice layer that protected the bodies. The research was published in the Proceedings of the National Academy of Sciences.
Lead author Takahiko Hariyama, of the Hamamatsu University School of Medicine, came up with the idea after making scanning electron images of fruit fly larvae. He noticed that the electron beam didn’t kill the larvae. Later, he found out that some invertebrates have a special kind of molecule in their cuticles (the hard covering on the outside) that when exposed to electrons or ionized gas forms a protective layer. Other insects have a similar molecule.
Hariyama’s team tested the Tween 20 on the animals that did not have that special molecule, and got the same result — the animals lived.
Not everyone is convinced, though, that this method offers special insight into living invertebrates. Shippensburg University entomologist Gregory Paulson told The Scientist that the coating itself might affect how small structures on the bugs’ bodies look.
Via The Scientist
Electron microscope image of a mirid bug (family Miridae). The insect is quite dead.
Credit: Dartmouth College