If you're watching the complex processes in a living cell, it is easy to miss something importantespecially if you are watching changes that take a long time to unfold and require high-spatial-resolution imaging. But new research* makes it possible to scrutinize activities that occur over hours or even days inside cells, potentially solving many of the mysteries associated with molecular-scale events occurring in these tiny living things.
A joint research team, working at the National Institute of Standards and Technology (NIST) and the National Institute of Allergy and Infectious Diseases (NIAID), has discovered a method of using nanoparticles to illuminate the cellular interior to reveal these slow processes. Nanoparticles, thousands of times smaller than a cell, have a variety of applications. One type of nanoparticle called a quantum dot glows when exposed to light. These semiconductor particles can be coated with organic materials, which are tailored to be attracted to specific proteins within the part of a cell a scientist wishes to examine.
"Quantum dots last longer than many organic dyes and fluorescent proteins that we previously used to illuminate the interiors of cells," says biophysicist Jeeseong Hwang, who led the team on the NIST side. "They also have the advantage of monitoring changes in cellular processes while most high-resolution techniques like electron microscopy only provide images of cellular processes frozen at one moment. Using quantum dots, we can now elucidate cellular processes involving the dynamic motions of proteins."
For their recent study, the team focused primarily on characterizing quantum dot properties, contrasting them with other imaging techniques. In one example, they employed quantum dots designed to target a specific type of human red blood cell protein that forms part of a network structure in the cell's inner membrane. When these proteins cluster together in a healthy cell, the network provi
|Contact: Chad Boutin|
National Institute of Standards and Technology (NIST)