A two-year collaboration between British neuroscientists and chemists has led to a new fluorescent dye that’s less toxic than other dyes on the market. The new tool will help researchers understand the mechanisms underlying many neurological diseases, including Parkinson’s.
Scientists at England’s Keele University in Staffordshire and Newcastle University in Newcastle upon Tyne designed the new voltage-sensitive dye. Known as JULBD6, the dye is illuminated with light in the red region of the spectrum, lowering its toxicity. JULBD6 also has a low signal-to-noise ratio, making it a valuable alternative to many currently used dyes.
Their study, “Locally Excited State-Charge Transfer State Coupled Dyes as Optically Responsive Neuron Firing Probes,” appeared in Chemistry-A European Journal. Researchers also presented their results at the Society for Neuroscience’s annual meeting, held Nov. 11-15 in Washington, D.C.
“This could have a large impact on neuroscience as a field,” Dr. John Butcher of Keele University said in a press release. “The structure of the new dye, JULBD6, is completely different from other dyes such as the widely used di-4-ANEPPS, but offers the same signal quality in terms of the change in fluorescence during neuronal spiking and does not affect the health of the neurons.
One of the ways scientists study events taking place in the body’s cells and organs is by using fluorescent dyes that can be visualized by various microscopic methods. Visualization of singling events — such as those involving the neurotransmitter dopamine — would offer insights into normal neuronal function. This could potentially lead to novel treatment approaches.
Current dyes for viewing neurons fall into two main categories: calcium and voltage-sensitive dyes. Calcium dyes have the advantage of showing stronger fluorescence changes, hence aiding detection, but are slower to respond to neuronal signals. On the other hand, voltage-sensitive dyes respond more rapidly, but have weaker fluorescence changes.
Yet light with wavelengths in the green region of the spectrum is more toxic to cells than light in the red region.
Dr. Peter Andras, also a professor at Keele, said the team’s results are very promising.
“We have shown a completely new voltage-sensitive dye that allows rational design of key molecular features and offers similar performance to other dyes which are widely used in neuroscience,” he said. “This dye is also in the near-infrared range, rather than some green dyes which have higher toxicity, making it more suited to longitudinal studies. This new technology could really benefit neuron imaging studies.”