"Our work represents the first time a biologist can image long-term phenomena within the nuclei of living cells," says Fanqing Chen of Berkeley Lab's Life Sciences Division, who developed the technique with Daniele Gerion of Lawrence Livermore National Laboratory.
Their success lies in specially prepared crystalline semiconductors composed of a few hundred or thousand atoms that emit different colors of light when illuminated by a laser. Because these fluorescent probes are stable and nontoxic, they have the ability to remain in a cell's nucleus -- without harming the cell or fading out -- much longer than conventional fluorescent labels. This could give biologists a ringside seat to nuclear processes that span several hours or days, such as DNA replication, genomic alterations, and cell cycle control. The long-lived probes may also allow researchers to track the effectiveness of disease-fighting drugs that target these processes.
"We could determine whether a drug has arrived where it is supposed to, and if it is having the desired impact," says Chen.
The first enduring look into the secret lives of cell nuclei comes by way of a strong collaboration between biologists and chemists. For the past four years, Chen and Gerion have worked closely with members of the lab of Paul Alivisatos, a Berkeley Lab chemist in the Materials Sciences Division and Associate Laboratory Director who helped pioneer the development of nano-sized crystals of semiconductor materials. Called quantum dots, these microscopic crystals have
Source:Lawrence Berkeley National Laboratory