Researchers discover new dye that could differentiate tumors from healthy tissue in the brain

Researchers, from both Rice and Stanford Universities, have found a new way to capture brain images, without an invasive procedure, that can distinguish healthy brain tissue from a glioblastoma tumor in mice.

Chemists Han Xiao, of Rice University, and Zhen Cheng, from Stanford University, teamed up on the study that used a small-molecule dye called, fluorophore, which is able to cross the blood-brain barrier, according to a press release.

“This could be very useful for imaging-guided surgery, for example,” Xiao said in the release. “Using this dye, a doctor could determine where the boundary is between normal brain tissue versus tumor tissue.”

This groundbreaking discovery could have a big impact on imaging-guided surgery and the detection of brain tumors in humans, the release stated. The study, which was featured on the cover of the Journal of the American Chemical Society, describes how the small-molecule dye is the first of its kind to be able to cross the blood-brain barrier. The fluorophore emits light that can penetrate deep into the brain, making it ideal for imaging hard-to-access structures and processes.

Fluorescence imaging has been used for imaging cancer in different parts of the body, but deep-tissue imaging requires longer wavelengths, according to the release. 

The researchers faced a significant challenge in the development of the small-molecule dye: the blood-brain barrier. This barrier acts as a very selective filter to restrict the passage of substances from the circulatory system to the central nervous system. The dye developed by the researchers is more compact than the other two known NIR-II dye scaffolds, making it a good choice for probes or drugs specifically directed to the brain. The researchers also found that their dye lasts longer than indocyanine green, the only FDA-approved NIR small-molecule dye for its use as a contrast agent. 

Several organizations supported the study, including the Cancer Prevention Research Institute of Texas, the National Institutes for Health, the Department of Defense, the Robert A. Welch Foundation, the National Science Foundation, the Hamill Innovation Award, the John S. Dunn Foundation Collaborative Award, and the Stanford University Department of Radiology, the release stated.