In order to monitor and decipher the interactions of brain cells, or neurons, scientists have resorted to a variety of methods including gold nanoparticle arrays, complex neurochips and simple cation-sensitive dyes. Researchers at the Tsien lab at the University of California, San Diego School of Medicine, however, have developed a new fast-acting fluorescent dye that improves upon the many shortcomings of previous (aforementioned) methods.
In their article for the January 24th Early Edition of the Proceedings of the National Academy of Sciences, the researchers described the ability of their breakthrough dye to highlight electrical activity in the membranes of neurons. Both in vitro (cultured) and in vivo (living model) neuronal cells intake the dye at a membrane level and under exposure to light, flash brightly enough to be captured by a high speed camera.
“One of the tradeoffs with using voltage-sensitive dyes in the past is that when they were reasonably sensitive to voltage changes, they were slow compared to the actual physiological events,” said first author and post-doctoral researcher, Evan W. Miller. “The new dye gives big signals but is much faster and doesn’t perturb the neurons. We essentially see no lag time between the optical signal and the electrodes.”
One of the most important aspects of the new dye is that it opens the doors for more accurate, single trial experiments. Previously, researchers would have to repeat experiments with cells and average results.
Dr. Roger Tsien, a lead investigator in the finding, is a Howard Hughes Medical Institute Investigator and 2008 Nobel Prize co-winner in chemistry for his work on green fluorescent protein. He has searched for a directly responsive, sensitive and accurate method of screening membrane voltage since he started as a graduate student in 1972 and believes they are “finally on the right track, four decades later.”
