If the key to winning battles is indeed knowing both your enemy and yourself, then scientists are now well on their way toward becoming the Sun Tzus of medicine by taking a giant step toward a priceless advantage – the ability to see the soldiers in action on the battlefield.
The technique involves taking two silicon-nitride microchips with windows etched in their centers and pressing them together until only a 150-nanometer space between them remains. The researchers then fill this pocket with a liquid resembling the natural environment of the biological structure to be imaged, creating a microfluidic chamber. Then, because free-floating structures yield images with poor resolution, the researchers coat the microchip’s interior surface with a layer of natural biological tethers, such as antibodies, which naturally grab onto a virus and hold it in place.
Rotavirus is the most common cause of severe diarrhea among infants and children. By the age of five, nearly every child in the world has been infected at least once. And although the disease tends to be easily managed in the developed world, in developing countries rotavirus kills more than 450,000 children a year.
At the second step in the pathogen’s life cycle, rotavirus sheds its outer layer, which allows it to enter a cell, and becomes what is called a double-layered particle. Once its second layer is exposed, the virus is ready to begin using the cell’s own infrastructure to produce more viruses. It was the viral structure at this stage that the researchers imaged in the new study.
Kelly and McDonald coated the interior window of the microchip with antibodies to the virus. The antibodies, in turn, latched onto the rotaviruses that were injected into the microfluidic chamber and held them in place. The researchers then used a transmission electron microscope to image the prepared slide.
The technique worked perfectly.
The experiment gave results that resembled those achieved using traditional freezing methods to prepare rotavirus for electron microscopy, proving that the new technique can deliver accurate results.
“It’s the first time scientists have imaged anything on this scale in liquid,” said Kelly.
The next step is to continue to develop the technique with an eye toward imaging biological structures dynamically in action. Specifically, McDonald is looking to understand how rotavirus assembles, so as to better know and develop tools to combat this particular enemy of children’s health.
This story is reprinted from material from Virginia Tech, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.